it can take ages to understand how rare and what makes a record rare there has been many with wrong spelling on centre circle or even wrong tracks specail pressing with extra track.
one of the main thing that makes anything rare and collectable is how many was released pressed.
lot of people think wow i have loads of elvis they must be worth a fortune that is not the case the more they sold the less rare they are
even with cd's they can be rare when they came out in the 80's not a great lot was pressed so a lot of the early ones can have value