Hi Hank,
I had over half the set . 15 total of the 25 to completion. All that I have left now are Alexander and Johnson. I found a group of 9 that were folded in half about 15 years ago. I often see ones I once owned in auctions with the fold. All had the sheen you were talking about. The sheen can dissipate if the item is subjected to being in the light a lot. The 9 I found with the fold were in a guys fathers filing cabinet all folded in half but looking great otherwise. I not sure SGC's criteria on anything and certainly not S81 silks or for that matter S74 silks. It is also hard to tell from your scan as I dont think I see all the edges. Feel free to send me an email and check out our tribute site to
www.S74Silk.com . It does mention the larger silks as well