X61T - How similar are models to each other for swapping parts purposes?

Question

I recently purchased an X61 Tablet at auction and am loving it. I got a great deal and it is exceeding my expectations already. (This isn't my first ThinkPad, though.)
However, part of getting a great deal on it is that it isn't perfect. It was sold as surplus, and saw years of constant use before it made its way into my hands. There are a few things wrong with it that I've noticed, including:
The center latch is loose. It locks, but it feels like someone who hadn't used a ThinkPad before pulled up on the top HARD a few times instead of using the switch.
The slot where the pen goes doesn't have a way of ejecting the pen: the piece that grabs on to the pen's clip had broken off and was blocking the entire slot, so I removed it. The way the part broke means that there is no easy way to reattach it.
I would like to get these fixed, eventually. Now for my actual question:
How similar are the different models of X61T to each other?
My computer is a 7764-CTO. I was thinking about just buying a 'for parts' X61T for these plastic pieces and to have some pieces to keep it alive for as long as possible. I'm assuming that the CTO ('configure-to-order') doesn't matter much and that any 7764 should work, but would a different model (e.g. 7767-XXX) be similar enough to buy for parts? I have reviewed the Hardware Maintenance Manual and they sometimes list different FRUs. However, it is difficult to tell to which FRU a part belongs (particularly the above parts). Moreover, I imagine that the FRUs may have different numbers but be functionally equivalent on occasion. 
For practical purposes of cannibalizing parts from one X61T to another, how similar are the different models (776X) to each other? I would hate to buy a 'for parts' computer and have slight differences render it useless for my purposes. Thanks!

Answer 1

X60T has a different (albeit swappable) LCD assembly, and utterly different palmrest and keyboard bezel. Couldn't tell you about the pen resting area since I've never looked into that...
Cheers,
George
In daily use: R60F, R500F, T61, T410
Collecting dust: T60
Enjoying retirement: A31p, T42p,
Non-ThinkPads: Panasonic CF-31 & CF-52, HP 8760W
Starting Thursday, 08/14/2014 I'll be away from the forums until further notice. Please do NOT send private messages since I won't be able to read them. Thank you.