Hey Chip....

if you aren't gonna paint'em in the mold... you can at least Prime'em in the mold... (If you aren't already)...

If the tools are aluminum or capable of elevated temps.... heat'em up a bit (100'ish maybe) and as you spray the primer down... lay it down
in light near overspray coats.. that allows the Solvents to flash off....
the added benefit of priming is that it will help eliminate the annoying pinholes that otherwise occur....

Added note.... (If you decide to go the Prime-first Path) ...be sure to use a solvent wipe on the primed surface even before sanding.... and make sure the solvent doesn't eat/dissolve what ever core material you use.... (Straight alcohol is a decent primer and doesn't affect most foams... 'cept I am not sure Rohacell likes it/?).. and as you prolly already know... wet sanding is a good way to verify the surface is contaminant free.... (IF the water beads up... the surface is contaminated)

If you are doing or already know the above... please disregard!! lol
(Prolly you have already gone thru all this on the fuselages huh??)