Blue could have been original. The factory has been known to overpaint pieces on occasion. Also, I believe the factory interior paint had an etching quality that sort of let it double as a primer. But, I wouldn't shoot color on the trap door without a primer base. Self-etching primers are available in spray cans. I'd spray a thin coat that just covers the bare metal so the grain appearance remains crisp before shooting color.
65 Hi-Po F/B (7 yr resto)
67 GTA F/B (small block) Mustang Owners Club of Austin (MOCA), TX
MCA 27479
http://albums.photopoint.com/j/View?u=1575609&a=11978710&p=43914197.jpg
65 Hi-Po F/B (7 yr resto)
67 GTA F/B (small block) Mustang Owners Club of Austin (MOCA), TX
MCA 27479
http://albums.photopoint.com/j/View?u=1575609&a=11978710&p=43914197.jpg