makes perfect sense, abc used various pressing plants when manufacturing a record, hence the varying label layouts and plastic variants i.e vinyl, styrene, once pressed, records were sent out on a sale or return basis, unsold stock was returned to abc to be recycled, a lot of the major labels adopted this policy, rca being a good example, obviously not every copy got returned, even a record that totally flopped on release would have sold a few copys, and probablly only around 80% of unsold made it back to be recycled, so there will be, albeit very few issues floating around, demonstration copys on the other hand were given out free and were not subject to the return / recycling policy, thaty why a vast majority of the major label stuff is more common on the demo format