I just started getting back into paintball all thanks to my lil bro. Picked up a Crossfire 68/4500 on ebay that was used once and has a hydro of 4/12 (not that it makes a diff). Anyways, got it in the mail today and on the bottom there is some small tiny bubbles. It also looks like there's no fiberglass beneath it. Is this defective or somewhat normal? My bro has a PMI and Empire tank and they don't look like this. Pic below.