Seat Rail Identification Help Request

Quick background, I bought this 1974 Duster recently (couple weeks ago - new to MOPAR vehicles too) and I'm starting to tear down the inside.

The car was setup for drag racing, so it had plastic racing seats and and a tiny Grant steering wheel (that's for another thread).

Anyway, can anyone tell me if rails in the attached images are aftermarket rails or factory rails?

Thanks!!!