Need to install new gas tank - help

[62lwbc10]

Hey guys im tired of the gas fumes in the cab and I just found that the tank is leaking in a few places along the bottom crimp, especially on the pass side corner. THInking to order a new one from classic parts for 144 bucks. Can you tell me is it necessary to also seal the inside with gas tank sealer? I was hoping not to do this and just to install the new tank as-is. Let me know and also if you have any other tips or useful info regarding installing a new tank.

Regards,
Mark