Capri Pearl was offered as a standard wrap for any drum offered in a wrapped finish. Here's a link showing the 2pc Jam Session kit from the 1963 catalog. http://vintagedrumguide.com/images/slingerland_drum_sets/1963A-slingerland5.jpg

-Mark

So, what's the best way to determine if it's a Radio King snare?

Check all the details. The black/gold Chicago badge covers the years '56-'61. From around '57 to '62 Slingerland did not use the Radio King name for its drums so technically those are not Radio Kings. You are left with about one year that could be a Radio King, 1956. '56-'59 Chicago badge will have the "looped S". If this snare is a Radio King it needs to have that badge. 1-ply maple shell would be expected. Engraved hoops would be a positive. Original strainer could be a clamshell or the three point. Does anyone know if the Capri Pearl wrap was even available in '56? Sounds like it may be a great drum regardless.

Here's the badge. It doesn't have the original hoops or three point strainer. It's an aftermarket three point strainer that fits into the existing holes.

That is the "looped S" badge used from '56-'59. What kind of hardware/extra holes on the butt side? Pictures?

Doing a little research here shows that Capri Pearl was first offered in '58. This snare is a '58 or '59 and technically not a Radio King. Still could be a great drum though.

Unfortunately I don't have any good pictures. I was told the strainer and butt plate don't look to be original, but there are no extra holes.

The wrap looks repo, though pic pretty poor. Grommet also looks oversized to me. Proceed with caution.

Did you go for it?