Hey Nicholas,
Ackbar does look to be discoloration bud. I could be wrong, but I believe the Taiwan variant has a warmer, yelowish green tone, the Ledy and HK are more grey in colour.
pics taken from www.stattoy-variations.DE
here's one of Marco's from the ledy discussion thread 1:
http://www.imperialgunneryforum.com/t2135-lili-ledy-discussion-thread#AdmiralAckbar
Kenner left, Ledy right:
Your PBP coo VI.2a with 'H' remaining Vader, has the correct accessories and yes, this variant can be found in Clipper mail away baggies.
these are Maikel's pics from the Vader 'Figure of the week thread':
http://www.imperialgunneryforum.com/t223-darth-vader-figure-variants-thread