Pontoon structure integrity on 1978 Hobie 16.

I'm wanting to purchase this used Hobie but I'm concerned about structure of the pontoons. On close examination both pontoons have 1) long surface cracks on the topside, similar to cracks caused by stepping on fiberglass. 2) considerable waviness down the sides, mostly this is noticed on the inside of each pontoon when looking from front to back.
The fiberglass does not have any holes but feels very thin. This Hobie has been sitting for a long time. It has several gallons of water holding in each pontoon towards the front as it sits tilted towards the front.
Does anything I've mentioned about the condition of the pontoons sound out of caracter for an older Hobie or were these made with fairly thin pontoon fiberglass and these types of cracks and waviness be considered normal and more important, safe. Thanks