my 1972 tank is rusty and my 1975 is pretty clean, see pics.

Thats nothing....
but if you choose to replace , Yes

this pic is of my better tank. my other tank is covered with light surface rust but it is enough to clog my fuel pump in minutes of running. I am sure with enough filters I could clear out the problem but then I would still have the surface rust ever present.

the brackets on top of the tank differ but i'm sure you can work around that.
Good to see the car is getting back on the road. The more running 914's, the better.

Use the 75 tank with wxpansion tank and swap the nippl on the bottom. 75 has two large nipples early has one large and one small.

Nipples are important

one of the nipples on the better tank is buggered, actually it seems to maybe only have some aluminum in the threads BUT I am going to have one port welded shut and have a nipple welded to the other since i am running a carb.

The threads look ok, just the first 3 threads look clogged with garbage. Need to chase them with a bolt or the fitting using a cutting agent or motor oil.