UPDATE: My source has his remaining sheets sorted and is ready to let them go. I think there may be enough people on the waiting list to get pretty much all of it. But, just in case anyone falls through, this is your LAST CHANCE. PM me for his contact info.
This is the correct VINTAGE material called "LSA" for "Low Sun Angle." According to the info I've compiled, the manufacturer made this material at ~17 louvers per inch. Then, a separate machine
compressed that material so it had 24-30 louvers per inch. As far as I know, this stuff was available only in two varieties -- standard (~17/in) and LSA (~24/inch).
If what I’m told is true, the machine that compressed it broke down and the LSA variety was no longer manufactured after about 1991. Due to a lack of demand, that machine was never repaired. I don’t know if it even still exists.
My friend has the correct VINTAGE LSA MATERIAL that was used to make TIE fighters, the Millennium Falcon, the Galactica, Sandcrawler, etc. In fact, I have a measurement from an actual screen-used ANH TIE that proves this stuff is a perfect match.