Artist Proof “The Triumph of St Valentine”

This painting is an Artists Proof of The Triumph of St Valentine by Warrington Colescott. I acquired it at an estate sale about a year ago because I absolutely fell in love with the abstract nature. It wasn’t until recently that I noticed “artist proof” in bottom left corner, lightly signed in pencil. Just from common knowledge I know artist proofs are the most valuable, however I recently have been told they hold no value because they’re commonly used as tax write offs to museums by the artist. Is this true? The only information I’ve found on this piece are past exhibits from when it was on display at the Smithsonian.