I am curious now, if someone is buying an unopened record I would think that they wouldn't have intention to open the record. With that being written, wouldn't it not necessarily matter if there were pressing flaws or pimples on the vinyl?
Also would a mis pressing be valuable anyway?
I've bought countless still sealed LPs over the years at garage sales and thrifts along with finding many in collections I've acquired. With rare exception, I buy records to listen to them, so I'll do just that.
I had a customer purchase a still-sealed Commander Cody LP through Ebay. He brought the record to me for transfer to WAV files & CD-R. I opened it, played side 1 and then side 2. It was quickly apparent that side 2 was a mispressing, a repeat of side 1. My customer was not happy!
In cases like that, mispressings are undesirable and detract from value if anything. OTOH, there might be considerable added resale value for a mispressing by a 'collectible' artist like The Beatles or Elvis, etc...