You should be able to see if the lock ring/sending unit is leaking just by jacking it up, no reason to drop the tank. Even if it is leaking from the filler neck grommet that can be remedied without dropping the tank, access possible through the trunk under the mat.
Any sugestions how to get the fuel gauge working right?. The dash is an Autometer. Last mechanic who socalled fixwd it, filled it w gas 3/4 and it stayed that way. I have to check fuel with a hose down the tank.