TCW --
The finish on the new PMs is quite different than the Express finish. Remington says that the Express finish is just bluing on unpolished metal. Coulda fooled me -- I would swear it's paint. Whatever it is, the Express *looks* like black crinkle enamel -- shinier and blacker than the current PM finish, and crinkled, too, compared to the smoother finish of the PM.
I may be splitting hairs. Most people refer to any phosphated finish as parkerizing, but this is not the case. Real Parkerizing is manganese phosphate, but many "parkerized" finishes are zinc phosphate. I don't recall the differences, although I think that the real Parkerized finish may be more durable. I suspect that the current finish is zinc phosphate. I don't know why they changed, but I assume it's cheaper.
I have a newer PM with the Vang extension and a Vang-modified Express tube. The extension is a close match. The barrel isn't, but it's a working piece and it's close enough for government work (especially considering the price I paid for the barrel).