Attempting to buy first pistol after getting my NY CCW permit. Any help appreciated

Looking to purchase a Glock 48 MOS as my first pistol.I found several used ones, with this being the most reasonably priced and closest to national average sale price.

I’m trying not to get fleeced and I don’t want to accidentally buy a POS. This price looked reasonable. However I have little to no frame of reference in regards to what is a good deal, or how to analyze if a pistol for sale is in good shape. A few things I already see is the seller is a pawn shop, I don’t know what is on the back of the slide. Some have said this site is ok to purchase off of. But any help or other recommendations would be very much appreciated in regards to price or where else I should be looking. Thanks

Edit: I am also unsure of how to verify it has the slide cut to fit a red dot. Located in Rockland county