Didn’t PP stop plating around 2005-2007 prior to the introduction of PP Seal? That could explain the whiter aspect of plated gold? Just an hypothesis 🤔 (I recall pondering on that question before buying 5127G)
Or did you mean different colors across models, which would be intriguing to say the least (as I expect metal for cases to be the same across models)?
Looking forward to hearing more from the experts here!
J.