Going at it chemically will likely damage the original artwork, unless you find something that is slow to react. If you wanted to test, I might paint a test surface with some acrylic paint, let it cure, then spray it with black spray paint, then test some of the usual chemicals. Alcohol, Goo gone, naphtha, goof off (contains some acetone), mineral spirits, and possibly even going as harsh as acetone. There's also various motsenbocker's products, but I haven't had great success with that on spray painted cabinets. Note that it would be best to apply the chemical to a paper towel or cotton rag, and not directly on the paint.
Sanding with very fine grit sandpaper might be a possible approach, but the original paint is not quite leveled to the same height, so you might end up sanding through the original masking and paint.
Mayfair amusement might have replacements in stock, though I'm guessing one would be just under the $300 mark.