Body plugs in a 71 b body.

I'm looking to weld up the plug holes. Problem is my cars been apart so long I forget which ones must be kept. I think there is one for the fuel sending unit. Do you have to keep the middle one in the trunk floor for access to the filler neck? Do you need to keep any more?

If you're still looking for an answer, let me know.
I have a '72 and a '71 parts car I could check out.
Not sure exactly where the hole is you're talking about-is your sender on the right side of the tank?
Emissions nipples were in a different spot on the '71s, that I know for sure.