There's a bat on eBay now that seems to disprove the theory that the "small oval, large 125" label variation was limited to 1983, or even 1982-1984. It's a Keith Hernandez bat that has the small oval w/ large 125 -- and a foil-stamped name on the barrel (which supposedly was done only during parts of 1985 and 1986). This bat suggests that either the small oval/large 125 was used as late as 1985, or that foil stamping was used as early as 1984.

Here's the link: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=60596&item=5192797989&rd=1

Just another example of how there are no absolutes when it comes to bat dating.