My guess is it’s a Crestliner that has had the misfortune of falling into the hands of a sawsall savant. The biggest clue is the pattern on the bow of how the aluminum is fastened together. You can see in one of the photos the remains of the sawed away bow covering on the gunnel.
I am pretty sure it’s not a crestliner, altered or not. I agree the rivet pattern is similar to crestliner but the shape of the boat at the stern doesn’t resemble the crestliner look. also there are no crestliner corner brackets and the transom handles are not the type crestliner used on their boats of this vintage.
I’m thinking a lone star, star craft or something similar.