They are alloy wings, although not immune to corrosion around the edges. I like Ivory (or Cream as the DVLA call it).
I reckon there aren't too many bobbies around these days who would notice anything wrong with R reg B&W plates on a Morgan. On the other hand, it wouldn't surprise me if a quick zap with some electronic device would prompt an on board computer to spit out an on the spot fine so you're probably right to play safe.
~iw
