I got a one sided record at an estate sale a few years ago in a box of records I picked up for five bucks. It was in a thick plain white jacket that had “Pepper” hand written on the cover. It had a “Mobile Fidelity” generic label. Turns out it was a test disk for one side of the stamper for side one of Sgt Pepper.
I’ve only played it once. It sounds like a CD - in the good way.
I’mm curious if you have ever had that test demo checked as to it’s value to collectors?