I believe the WOK suits didn't have the stomach pleats, so I think this is a later style. Also the WOK suits didn't have the wide cuffs with the stitching on them either and the fabric looks different.
I could be completely wrong though.
IIRC, the Admiral's braid on the cuff was different in TWOK compared to the following movies - think it was a checkered-pattern braid as seen on Battlestar Galactica TOS uniforms. The above braid was used from TSFS and onwards.
Here's some more info on the chain-
You want the one at the very top, #703X Nickel Plate.
Here's the link-
http://providencechain.com/Other styles.htm
and the 800 # - (800)783-1499
As far as I know, this was the only style used on the hero uniforms, but they may have used something cheaper for the background guys.
-Sarge