The Rover-Landers of BC

So the fender gaps on my 2A are as clean as I will ever get them right now and I have one coat of pain on.

Should I fill them with paintable epoxy/mastic/flex seal??? Thinking of a paintable seal or just color match seal after paint is done.

Typically from the factory I would say there was generally no gaps in the fender joints but over the years when the panels get older, have been on and off a few times, had a few bashes then the gaps do tend to show up. I have seen gaps removed by carefully working the seams with a small hammer but there is quite a craft to working with old aluminum panels.
If you go the filler route, I would use a flexible, paintable filler / caulk but ensure its concaved down into the gap. You want the fender lines to show up, just not the gap. If you need to remove the panels at a later date a quick slice through the caulk will make it easy to remove.
For the best result I would fill the gaps before painting unless you are painting each panel separately hanging in a spray booth
Cheers
Andy

Awesome thanks! Yes they are off the truck right now, so painting should be ok. My spray booth is big and airy and looks like my front yard ahahahah