Vandy 2 signature upgrade question

Need some far back can you go in the Vandy 2 line and still ship them to give them the "signature" treatment? Also, has anyone done this? What were the results?
While I am not an authority on this, you really should call Vandersteen to verify, the entire model 2 series is NOT upgradable. I had 2Ci's for about ten years and never came across any upgrade information. The Vandersteen website says nothing about it either. I aksed Richard Vandersteen about this a few years ago and I beleive his reasoning was economics, a $1300 speaker can't have that built into it, whereas the $2500 model 3 could (of course the 3A Sig is now $3500!).
They have to be 2Ce's. I know my 2Ce's are even too old. There was a cut off in the serial numbers of 2Ce's for the upgrade. It used to list the info on their web site. It is gone so I assume that they don't do the update now. You will have to make a call to your dealer to find out. I wouldn't call the factory!
I don't know if it is still on the Vandersteen website or not, but the info that was PREVIOUSLY posted as regards the ability to upgrade from 2Ce to 2Ce Signatures was"

"MUST Be ABOVE Serial Number 77,000 for Upgrade to 2CE Signature - $350"