CONTINUOUSWAVE

Q1: should the presence of some non-OEM snap fasteners affect the decision to purchase an otherwise "super" clean 130 SPORT [of unspecified model year]?

Q2: if subsequent inspection determine that other than these non-OEM snap fasteners the boat is "clean" should the presence of these non-OEM snap fasteners be overlooked?

BACKSTORY
I may purchase [an unspecified model year] 130 Sport that has three snaps installed on each side of the exterior of the hull for a custom cover. The boat is in super clean condition. My only concern is whether snaps that are drilled into the hull will potentially cause water to get into the foam as they are in an area that will definitely get wet. I have no way to verify if these snaps were properly installed or whether they were installed into a reinforced portion of the hull.

You can always pull the snaps, put some silicon sealant or 3M4200 Adhesive on the screw portion and reinstall the snap fasteners.

If the finish of the snaps is compromised by corrosion, replace them with new. Old crusty snaps just aren't worth the aggravation.

The presence of a total of six non-OEM snap fasteners on the hull does not sound like a particularly egregious error in the addition of a cover. If you really do not like the fasteners, they could be removed and the holes filled with color-matching gel coat resin. Then some other method to hold the cover to the hull could be invented that suited your preference for avoiding non-OEM fasteners into the hull.

Buy the boat, reinstall the snaps to your liking and move on.