Should I put seam sealer on my floors?

I'm currently sound dampening the floors of my 67 coupe (i'm using products from secondskinaudio.com, btw - which I've found to be both better & cheaper than Dynamat), so I stripped down the floors to the bare metal and applied 2 layers of Por-15 to them.

However, before I do a topcoat of chassis black, I was wondering whether I should apply seam sealer between all the plates? Is it really needed when I'll have 3 coats of paint + 3 layers of sound dampening on top?

Oops, my bad - after using the very handy search function, it looks like the consensus is that I should apply seam sealer after doing the POR-15 treatments. So unless somebody tells me otherwise, I'll do just that