74 Roadrunner rear bumper filler

This has me stumped. Bought a builder 74 Roadrunner last year that had been pretty well disassembled. The owner then came down with a bad case of Lyme's disease, had to quit his job and sold the car. I don't particularly like this body style but it was priced fair and I felt I was helping him out.

Getting close to painting it. Sizing things up for fit and I've discovered there's quite a gap between the top of the rear bumper and the trunk lip. Is there supposed to be a filler panel there? I've looked at photos but haven't found anything that answers the question for me. I hate to paint the car and then find out about it, since I assume it would be body color.

Thanks in advance for your input.

Yes, there's a filler strip for the 73-74 rear bumper...Actually two end pieces and one center.... End pieces bolt to the bumper{and can still be found used in good shape} and the center strip has a metal core that grabs the top, inner lip of the bumper...And you can go ahead and paint the car... The filler pieces are not painted body color...The finish is{as moulded} silver... And you're in luck...The center strip was like gold for a few years but there's a repop now...{Frank Mitchell}Here's the link... rear bumper filler

Thanks so much for the info. Much appreciated!