Adjustable seat tracks

I just picked up a pair of black buckets and rear seat out of a 73 Duster 340(this is what the guy said they were out of)and I noticed something i'd never seen before. The seat tracks are made to be adjusted up and down to change the angle of the seat. As the pictures show, it appears to be factory.Part of the broadcast sheet shows it was a 340 or 360 Duster
Has anybody seen this before?:dontknow:

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Author: admin