R14 is not populated. Hard to say, but it looks like a modification and not original. I can't check R74 easily since it's on the other side, but it does seem like this is a modded 33 MHz LCIII, which is probably why the standard installer wouldn't recognize it.
Yes, TattleTech reports Performa 460, 33 MHz MC68030! Everymac says the P460 requires System 7.1P or later.
One small puzzle remains - I've installed a VRAM SIMM, which should be enough to get 832x624 at 16-bit, but Monitors control panel only offers 832x624 at 8-bit. No big deal.
This LCIII/P460 was supposed to be a give-away prize for the Tetris Max high score contest, combined with an LCD and keyboard and mouse. It was assembled from mostly cobbled-together parts I had lying around. But now that it's working I'm not sure I want to give it away!
Everything is in really nice condition, the logic board is recapped, the plastic is nice... it's actually the best 68K Mac in my collection now. If I were so inclined, I could probably sell the whole system for a decent amount of money, but it's more fun to spur interest in the contest.
So here's what the expert Tetris Max player can win:
Performa 460 (in a Performa 405 case)
33 MHz 68030, 4MB RAM, 768K VRAM
external cosmetics 9 out of 10
80 MB SCSI HD with System 7.1 and custom software collection
Apple Keyboard II (or maybe AEK II instead)
Apple Desktop Bus Mouse II
Viewsonic VG900b 19 inch 1280x1024 LCD (or possibly Viewsonic 6 14-inch CRT)
VGA cable with DA-15 adapter
everything tested and working
Price: $0 or best offer