The game itself was finished in June 22 of 1995 or around then, it's an internal time stamp on the game we've been bootlegging to play, and the game was plotted at first for a Summer 1995 release
but Miyamoto being an idiot canned the game thinking the N64 would be out a year earlier and wanted to get away from old crusty 3D on SNES.
As far as the alpha(beta1), beta 2, and (final) beta 3 (release candidtate) it's hard to peg down. In the later 90s there was this website called cherryroms that released well ROMS (they got busted some time later so it's long dead.) They had the game listed as undumped, but then pulled it between May and Sept of 1999, so some version of it popped up that early on and supposedly that was the alpha that just had a few flight tests, odd menus, little combat or of anything to do. The game we fell in love with from the CES in the 90s was farther along than this file however it got out. I'm not certain when beta2 popped up, but I do remember that the final test release beta, that came out in August of 2002.
There's some history well more detailed on this at snescentral.com if you want to dig into it.
It states what we're playing with is the final game, but it just doesn't have level select, framerate indicator and poly count per scene, level skip cheats etc removed. To be clear though since that period there are 2 versions of the final beta out there. There's one with that stuff still there, then the rom hacked version that cleans the stuff out as the developer said they would have and makes it entirely stock to an actual release with the test stuff removed.