To the op.If you soak a rag in paint thinner ( mek,methyl ethyl ketone) or acetone which is more agressive,and you can wipe the surface for up to 15 seconds without appreciably feeling it go soft and tacky (starting to grab the rag) it's almost sure to be epoxy or sim blend.In which case you can just give it a light sand and paint over it.I like using a single pack clear adhesion promoter when i do that.Paint stripper on a glass part can be effective if you do small areas quickly and have done it many times before.If you are stuck with a finish that is easily softened by any thinner,you could sand and spray a light coat of 2 pak clear primer sealer and paint straight over that,save you heaps of time.Good luck.