David:
This looks like original paint and one of the simplest things to do would be to look at the frame under an ultraviolet light. I purchased an Andy Gilmour frame and the only way to tell exactly what it had been was to see the evidence of the long gone Gilmour decals under ultraviolet light. They're back on the bike now and Andy Gilmour did confirm that it was one of his creations. For what it might be worth.
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Mark Pounders
Richmond, Virginia
USA