Is this a fair deal to rebuild my transmission?

[1972BlueC20]

@jimbosprint, nah I don't think it really matters if you have the same transmission. That is, from what I've been told on here and by a few buddies. I mean for purists, yeah it's always nice to have a totally original truck, but these trucks aren't usually super rare or show trucks. They are for pleasure. I think numbers matching is more engine to chassis number matching but I stand to be corrected. I'm fairly new to classic cars / trucks. I'm not sure if transmissions have any markings that marry them to the engine / Chassis or truck. Can anyone verify?