Alan....I would hazard a guess that as long as you seal the pinholes from exposure to air/moisture,i.e. POR-15 inside and top coat outside you shouldn't have any probs.
Just remember though,if you just prime the outside after filling,primer is porous and will allow moisture in.
Best to get the paint on as soon as possible!


1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.