I can think of two possibilities.

1. Several drum companies used a date stamp consisting of a two digit year followed by a two digit month in the 1940s. A Code 4906 would translate as June 1949 in this system. If Gretsch used this system it would have been before about 1947 when they used a "XXX ## 19##" format which included a three letter month, 2 digit date and four digit year. See examples from 1947 and 1950 attached.

2. Gretsch used a four digit code in six lug snares during a period before the paper labels and after the introduction of the silver sealer interior paint. I have recorded 27 different examples of this type of thing with numbers ranging from 817 to 5189. I have not figured out the meaning of the stamps. I have attached a picture of one example. Does your look the one attached?

For comparison, here is a September 1938 Ludwig tom with the four digit - year/month - style date code.

Thanks so much for all of the information! My snare drum interior stamp looks exactly like the second picture you posted with the silver interior. Do you know what the date range of these snares was? I'll try to snap some pictures tonight or tomorrow for you.

Andy

At this point, I have only been able to narrow down the date of the interior stamps to after the start of the silver sealer (about 1954) and before the introduction of the paper label (about 1962). For your drum we have one piece of additional information -it is 6 ply. The number of plies increased from 3 to 6 some time in the later 1950s/early 1960s (although this date is not nailed down and opinions differ).

Does it have die cast hoops or use hoop clips?

I completely forgot about this thread. Life got busy. My drum does have die cast hoops though. Here's a picture of the interior 4906 stamp and one of the exterior of the drum.