Bucket sets I.D

[jobrla]

Afternoon. I have been doing a complete frame off restro for 2 years on my 72 K5 blazer. The ONLY thing that is original is the frame and panels. All bolts, screws wiring, drive train, controls, ell you get the picture. $ 42K invested, that's with me doing all the labor. All I need to complete is a set of 71-72 bucket seats. I know the foam pattern for the 71 and 72 are the same. I purchased, sight un-seen the attach photo of a pair of bucket seats off CL. The bolt pattern is the same and the passenger seat tilts forward and locks in the floor panel latch. I know they had to come out of a blazer due to the bolt pattern and the latch. Does anyone recognize what year they came out of. They are completely flat, bot bottom and backs with no coving to the sides.
Any information would be very appreciated.