Scott 5015 Presort First Class Blue Is It Tagged?

To try and determine if the 2015 Spectrum Eagle was tagged I wanted see if the greenish overall color visible under SW UV was a coating. In the image below I took and rubbed a little bit of acetone on a spot in the upper right. If you look at the white area of the eagle's head you can see that there was clearly a coating applied that was removed by the acetone. This left the underlying base paper exposed. Acetone can remove overall taggant as well as any ink printed on a stamps. if the coating isn't an overall taggant then what else would it be that is SW UV reactive.

I checked with Rudy de Mordaigle and he has confirmed that the 2015 Spectrum Eagles are overall tagged. He indicated they are printed on non-phosphored Type III paper per the USPS Bulletin. The bulletin just doesn't indicate they were tagged.

Thanks Mstocky! Pretty interesting that Scotts and the USPS bulletin wouldn't included that detail or as from Scotts have it wrong. So now I wonder if there are any non-tagged 2015 and tagged on prephosphored paper 2015 varieties or errors?

Hi Mstocky since you were so good at solving this mystery do you have any comment on my other stamped envelope topic?
Different Colors, Different Catalog Treatment - U590 that one glows orange.