When I did the bed on my '47 I primed all the pieces first. Then assembled them, then shot the color. Now I would Prime everything first shoot a couple coats of color then assemble and shoot the finish color.
I guess the hard part then becomes the finish on the inside corners of the bed. I was planning on using a brush on bedliner material in my 50 1 ton.


1950 Chevy 3800 1-Ton Long Bed
In the Stovebolt Gallery
More pix on Flickr

Sold all the bikes, leaving California behind.