Fuel tank sending unit... does it merit replacement?

[rainamy]

The next system just about ready to redo on my 77 is the gas system when has been leaky since I've owned the truck.

I've got the tank out of the truck, and all the rubber was rotted up - the usual age + ethanol = bad things.

Now, I know the send unit to fuel line hoses were garbage. There is staining down the side of the tank from the send unit. It may be much or all of the source.

But I also took an inexact approach to testing the top for leaks - flipped the tank over with the in/out lines plugged on the send unit. There was seepage after about 1 minute sit time. (Pics attached)

I really don't want to put the tank in and yank it back out for another leak. Tank itself is nearly rust free (no scale/pitting, a couple areas turned light reddish brown powdery on the surface).

I'd think the tank should be leak free in my improvised test. I guess the o ring could be damaged but I wanted to leak test before taking apart since send unit is surface corroded from the leaking rubber lines on top.

Old gm parts (if reusable) are better imo than what's made nowadays... but... anyone have advice?