I have some catalog information and your "Peacock" finish looks like it showed up in the 55 catalog. I don't have 56 or 57 catalog info but the finish was also in the 58 catalog. The Microsensitive strainer is in the 55 catalog (even in my 54 catalog too) but I don't see a mention of the Peacock finish in the 54 catalog. It could have been around but not an option in the catalog. I would guess your drum to be 55-57 and maybe 58 (one of the drums without the silver sealer for that year if there are any).
NOTE: You might consider buying a new-for-2011 Gretsch Microsensitive Strainer and Butt Ends. They are beauties. I bought one for my 58 snare drum - they work like a dream and retro-fit to the snare drums that fit the Vintage MS Strainer & Butt End. The snare keeper plate screws (the screws that hold the snare plastic or string) have been replaced by drum key screws - as you can see in the video here = easy no-fiddling with tiny screws. The "Bat" arm is an integral part of the mechanism and will not break off like the original. This Bat lever now has a thumb release button at the end which you have to push to release the snares = no more "surprise" snare release because of a worn internal part like the original. They are well worth the money. If you ever try looking for a Mint or near Mint Vintage Strainer you will see they go for anywhere from $200 - $300 or more - if you can find them.
View the demo here:
[ame]http://www.youtube.com/watch?v=eize23RuUTM[/ame]
I retired....Zip-loc bag on the Vintage Drum Museum shelf haha...the original strainer. That way I can keep the proper part for the drum for "Vintage" purposes and it won't wear out.
No - I don't work for Gretsch OR Steve Maxwell lol - I'm just a very happy customer regarding this part............way to go GRETSCH !