I don't know.   With better pictures it might have been more clear.   But in the picture I showed, it was in the shadows, not direct light like the hi-toms.  So the different color wasn't really as obvious as it seems in hindsight.  And the mounting hardware is a bit blurry to easily notice the difference.

I'm guessing I'd have to remove a head to get more info on the shell?

Yes, the Slingerland floor tom will affect the value of the set negatively.  It's interesting that it has Ludwig leg mounts (or at least one of them).

So looking at the picture of the floor tom you posted to the gallery, it is from '55 or '56. August '54 to early '55 if the hoops have Slingerland Radio King engraved on them. The "dog tag" badge and large Sound King lugs on toms ended in '56  The leg mounts are Ludwig and replaced the bent steel brackets that Slingerland was using up through '56. You can see the extra hole from the old mounts under each Ludiwg mount.

Very cool all by itself.

Slingerland did not put badges on their toms in that era.  That may be a repurposed cocktail drum.

if the hoops have Slingerland Radio King engraved on them

I don't see any signs of any engraving.  But when I took it into a shop to get the heads replaced (maybe 20 years ago), the guy at the shop did say they were a softer metal that "was desirable but not made any more."  I'm guessing he probably meant chrome over brass.

You can see the extra hole from the old mounts

I saw the marks but didn't realize there used to be holes there.  The holes must have been filled in maybe with some type of wood putty. 

Very cool all by itself.

Yeah, that blew my mind when I saw the dates you posted

That may be a repurposed cocktail drum.

Sorry, not sure what that means.

Ah, good point.  That would be a lot of work to shorten a cocktail drum and reinstall the rering.  The location of the badge seems perfectly centered too. Not sure where the badge would be on a cocktail drum, assuming they had them.  I think I have seen an occasional older floor tom with a badge on ebay or reverb, but I could be wrong.

EDIT: Looked at the catalogs and the Slingerland cocktail drums of that era were 14" diameter so that would rule out a converted cocktail drum, assuming the floor tom is a 16".

It would be interesting to see pictures of the inside with the top head removed.

I'm pretty sure it's 16x18.  Definately not 14"

Although interestingly enough (not sure it means anything), the guy at the drum shop had a hard time finding a head that was a good fit.  Most 16" heads were just a little bit off.

EDIT: I'll try to get those inside pics sometime in the next day or two.

Uploaded the interior images of the tom into my gallery.

Double checked, no etching or engraving on the hoops.

And FWIW, the shell is a 18" diamater and 16" tall.    Is that correct to say 16x18 - or should it be 18x16?  For some reason I thought the diameter came first.

Ok, now we are getting somewhere. 

That is a 16" x 18" floor tom.

The size dimensions can be listed either way, but the most common way to do it has been Depth x Diameter.

That is not a common size, especially for back then. That might explain what it has a badge but as slingerfan said, they didn't normally put badged on any of their floor toms back then. Most people used a 16" drum. Few used anything larger, although Gene Krupa used a 20" x 20" at that time!

Anything 18" and above came with four legs, as yours has and at that time would have been straight legs. 

Drum shells back then tended to run a little larger than modern shells. Back when that drum was made, mylar heads had not come to market yet, so calfskin heads were the only option and they had wooden flesh hoops so there was more leeway to fit a head. 

Remo makes some heads aimed at these older drums. Aquarian American Vintage heads also should fit as they are slightly oversized for the old shells.

The mounts on your drum are actually for rack toms, because of the nuts instead of wing nuts. They both used the same bracket in eyebolt, they just used the wing nuts on floor toms, but that is no big deal. 

Other than the floor tom legs, everything on the inside says factory correct to me. From what I can see, the badge grommet looks untampered with on the inside, and it is a correct grommet, so it is probably factory.

The reinforcment rings look correct that that era. They were narrower than they were just a few years earlier, but wider than they would be in a few years. 

As I said before, since the hoops don't have Slingerland Radio King engraved on them, then the drum is a '55 or very early '56. Very early in '56 they switched to the smaller lugs on all toms and introduced the new floor tom leg mounts and introduced the black and gold badge, which still wasn't normally put on toms, but that does still help date your drum.

A cocktail drum was a very tall shell but 14" in diameter. It had legs and some had a head on the bottom and the ability to strike with a special bass drum pedal. You could play the top head with sticks and some even had a primative snare system on the top head.

I am including a couple of catalog shots from the '55 catalog and a picture that I borrowed from ebay of the proper floor tom bracket that would have originally been on the drum.