I figured as much, just joshin' with you.
So it sounds like you've got the trans apart at the moment. If you do it'd be the best time to find out what the gear ratios are by counting the teeth and doing some calculations. From my research there are at least two Z specific FS5C71-B transmissions (excluding nissan comp gearsets), three FS5W71-B transmissions and the 300ZX FS5W71C transmission as well as multiples of each from other Nissan applications. If it was mixed and matched it could contain bits from a 200SX, 300ZX, 810, etc...
I'm in the same boat as you though, I've only really ever heard of bellhousing swaps, not many swaps with the entire gearset. There are a few guys over at ratsun.net that have done some side by side comparisions of a few transmissions, and you might enjoy the reading here:
http://forum.ratsun.net/showthread.php?t=8978