Pink Floyd LPs

I just thought I'd share with you what I just picked up at a thrift store. I found a half speed "audiophile pressing" of Wish You Were Here (HC 33453) in very good condition and Dark Side of the Moon (SMAS-11163). The sleeve is nice and the record is mint. I don't think this record was out of the leeve many times as there isn't a dust particle on it. The two posters are still inside along with two Pink Floyd stickers.
These items set me back $2.00 minus 25%.
The DSOTM cover has a hole punched in the top right corner. What is the purpose of this?