I'm looking to buy one of these w/o the hammer block safety (they couldn't have made it more ugly), but have noticed they seem to come in a few variations: some have checkering and some have monte carlo stocks. Can someone tell me what all the variations were and when they were produced (or point me to some reference that has this information?). Thanks!

This is not an easy question to answer. The earliest Big Bore rifles were the .375 Top Ejects as you already know. These came out in 1978. I am attaching a picture from the Gun Digest of that year. When the Angle Eject appeared in 1983 the rifles had a Monte Carlo butt stock and the early rifles have the forward scope base holes drilled at an angle. I have included a picture of this type mount holes and a picture of a later Big Bore rifle with in-line holes and XS peep sight. You can see the plug screws sticking up on the forward receiver ring. The first review I am aware of the Angle Eject rifles is from the November 1983 issue of the American Rifleman – “A New Angle For The Model 94” by Edward A. Matunas.
There was an economy versions of the Standard Big Bore offered in 1985 without checkering and with plastic butt-plate. These are drawing some attention from collectors now.

There are some posters on the Beartooth Board who are far better informed than me on the time line of these rifles. Blackhawk44 comes to mind but I don’t believe I have seen any posts from him lately.

I hope these pictures show detail. I tried to make them small and yet still illustrate the differences.