Resealing the magnum..

I wouldn't pull the heads if there is no issue there. Everything else sounds like a plan. Hughes plenum kit, good gasket set, maybe put a timing set on it while its apart. Yes, 130k is nothing. I have had several of them and 300k is not a problem. My old 5.2 out of my Dakota had 192k when I pulled it to swap the 5.9. You could still see the crosshatch in the bores and pushed the pistons out by hand with zero ridge.