mtd were no different from mlp or red they all got stuff from boreham and built up cars into rally winners. you probably would find they did use stuff from salvaged cars as loads of them did back then as there was mint parts about on damaged cars.
i know a couple of lads who sometimes worked on mtd cars.
my mate had some very sexy mike taylor developments motordrive kevlar rally seats he bought of adrian farrell who owned welsh area rally spares. they were 800 quids worth new and came out of a works spec 3dr rally car,MTD used Motordrive seats with MTD written in the headrests, if your restoring the car please contact Alan Whitikar as he can tell you more about MTD and sell you the correct seats the would of used when new.

http://www.motordrive.com/acatalog/catalogbody.html

i'll find the pics and whack them up.

cheeRS Karl