I suppose anything is possible, but I really doubt it is cracked from heat. There would be some deformity along with it. It probably took a good whack with a spare tire, jack handle, or propane
tank being loaded/unloaded at some point. Less than $20 to patch on your own (from the inside) and have it plenty strong and watertight.
Really no idea on the cosmetic repair stuff. You'd have to talk to a boat builder or the like.