When NHL'94 was released (Sega Genesis), the first editions came with a sticker that said "Limited Edition 1st Round" and had a serial number. Mark Lesser actually has "00001" in his basement, which was seen as part of @McMikey's documentary "Pixelated Heroes". Here's an example of what the stickers look like:
I have been looking at these numbers for a while and recently decided to start documenting them because it was bugging me. From the small sample size I gathered (mostly eBay listings), my guess is there were 30,000 Limited Edition copies, however I don't know what the letters represent. Factory seems doubtful given the scattered nature of the numbers. My guess is the letter was some kind of lot size, or shipping destination, etc.
So far I have found EDIT: A,B,C,D, (no E), F, G, (no H) FOUND H, thanks Smozoma, I, J, K & L A - L!. Below is the running tally, sorted on the left by number and then by letter on right.
If you happen to own a copy or find a number that is not listed, please feel free to reply to this thread! I frequently search eBay listings, so as other 1st editions come up there I will incorporate as well.
Lowest number (aside from 00001) - 31
Highest number - 28,270