Just curious if anyone knows..

Actually VPI tends to make incremental improvements. Almost any turntable they ever made can be upgraded as they make advancements. 
That is why their older turntables sell for so much on Audiogon. And they all sound good. 

You have a great turntable.Enjoy it.

Ask VPI...They are known for great communication and honest answers to questions, great company.

I guess you guys were not around when Audio Research rose to pre-eminence based mostly on HP's adoration of their amplifiers and preamps.  The SP3 preamp went to 3A, 3B, etc, in a matter of several months.  I cannot even remember where it all ended with that model.  The Dual 50 amplifier rapidly went up to at least Dual 50F-1B.  On the amplifiers, it was almost a necessity, as the Dual 50 had a habit of blowing up for one reason or another, and Bill Johnson was constantly making changes to improve reliability, which in turn affected sonics.  My good friend, who owned a Dual 50, was in the habit of saying that the amp was only safe when unplugged.VPI changes names, rather than adding suffixes.