36" Avedis Zildjians aren't likely:
http://www.vintagedrumforum.com/showthread.php?t=11808
and certainly not from the 1940s. I've recorded two sales of 30" ones (both 1970s) in my database. I've also watched a mis-measured 40" shrink to 30" (one of the two 70s cymbals) when it was actually purchased for $600. The seller was absolutely sure of the 40" until we convinced him to actually measure it. There are 26" and 28" cymbals which come up for sale as well. I've recorded 22 sales of those. Those include just one 26" Trans Stamp, but from the 50s not the 40s. The most commonly found trademark stamp for those big ones is Mid 1950s (the Large Stamps).
I've also got prices for all these sales and the big ones aren't really "big bucks" compared to say old Ks. Around $500±$100 for 26" and maybe a bit more for a 28" although I don't have enough sales to get a sufficiently robust estimate. Just two 28" sales in addition to a couple of 28" gongs. This doesn't stop the dreamers who hope for "big bucks" like this guy with a 28" and a questionable story and identification:
http://www.vintagedrumforum.com/showthread.php?t=58616
There is no harm in asking very high prices. The cymbal just isn't likely to sell at the asking price, or for a very long time. In the case of the 28" (in the thread I've linked to) it just sat around and eventually disappeared from Reverb -- I suspect it went to a much lower best offer. It was down to $900 from $1500 (and not selling) when it went away. And the $1500 one on eBay didn't sell either. No takers at that price.
Pricing research isn't rocket science. Neither is the identification of production era from production clues (hammering, lathing, bell shape, etc) and/or trademark stamps.
Now the stamps he (the rep)was saying that zildjian does not nor ever did keep records of there stamps and give cudos to those trying. but the the trademark only last so many years. I think he said 12 so the repeated them through history so to not loose them funny the things you learn at the show ! So there goes stamp dating lol...
This story is quite misleading, although yes it does get repeated quite often. Here's why it is misleading.
The Avedis Zildjian trademark stamp we all know and love is covered by a trademark. This Trans Stamp one:
[img]http://black.net.nz/avedis/images/trans-14-stamp.jpg[/img]
and this late 50s one
[img]http://black.net.nz/cym2013/50s.jpg[/img]
and this 70s one
[img]http://black.net.nz/avedis/images/70s.jpg[/img]
The Trademark and Patent Office doesn't care about the presence or absence of three dots in a triangle or whether the U.S.A. has dots or just reads U S A with no dots. They don't care about slightly thicker lines. They don't care about subtle differences in the Ottoman section. The USTPO site is a public reference site and you can go and read up on the rules for yourself. The trademark from 1929 to present is just one trademark. There are different dies used, and we can tell them apart by little differences. But that's something the USTPO cares nothing about. That's just us finding ways to distinguish them. Like the ability to tell the 1 3/16" 60s stamp
[img]http://black.net.nz/avedis/images/15-914-short-60s-rule.jpg[/img]
from the taller version
[img]http://black.net.nz/avedis/images/22-3482-later60s-ruler.jpg[/img]
by subtle details.
Yes, you need to file a certificate periodically to state that a trademark is still in use. You can go and look up the number of years but it doesn't matter because this is all one trademark. Yes there are a few other trademarks which the Avedis Zildjian Company have used, for example: A Zildjian & Cie (1973-1987 -- and also in two different forms) and the A Zildjian and Cie Vintage. But interestingly both of these trademarks have been abandoned. You can find most of the other trademarks on my site, but not all of them are there yet.
So the reuse of particular trademark dies is unrelated to having to file a continued use certificate. If trademark die reuse exists (yet to be determined) it is more likely for other reasons. One reason which has been suggested is that if a die breaks during use the person running the machine would reach into the drawer and pull out an older one rather than stop production. In that case we might find the occasional cymbal which has a specific die stamp which seems quite different from what we we would expect given the other production features. None of this would stop us from recognizing the correct production era from the other production features. As BosLover said, we can't pin one cymbal down to a specific year (until the laser stamps appear). But the general ordering is fairly well understood.