I would say check the tanks, unless you know for sure that they didn't leak earlier. I would also say that it would be difficult to impossible to do a valid inspection while in the wing. As long as you are doing some patching and touchup prior to paint, you might as well pull the tanks. I don't know what covering system you are using, but remember that the Poly Fiber materials will NOT be compatible with any "dope" system!
If you want an essay on fuel tank inspection that anyone can do at home.......let me know