Spider-man #300 Hand Painted Animation Cel

Here's an interesting piece of animation art, it's hand painted cel of Amazing Spider-man #300 with unknown origins, but likely 90's era. It included a piece of parchment with paint codes on it for Spidey, his eyes an feet, and the beige webbing . When I first aquired it, was hoping it was a test model cel or even a "Studio-style" cel of some sort for the black costume in Spider-man the animated series but it's just way off from that. Could have been used for marketing materials, a poster, t-shirt, maybe even Toy Biz concept art?. But why it's painted on a piece of acetate, besides for animation use, is beyond me especially since the paint codes match those used by American cartoon companies.. There was a sister cel to this one with the red and blue costume too. Thought it was cool so I picked it up.