Ok, here is the latest addition to the set. I recently acquired these two Pinkertons. The McBride measures 4 x 6, is on thin photo paper and appears to have a thin paste residue at the top of the back. The Lord is 3 11/16 x 6 and is on the thicker postcard like stock, clearly it is part of the mystery set. I am unsure what the McBride is as it appears larger that most Pinkerton T5 photos.
Pinkerton McBride front.jpg Pinkerton McBride back.jpg
Pinkerton Lord front.jpg Pinkerton Lord back.jpg
Pinkerton-McBride---Lord.jpg
The photo quality on the mystery set is clearly superior.
Also of note is the Van Oeyen 1910 copyright embossed on the Lord. It is printed in the photo and is not applied directly embossed on this photo. Nice evidence of the age and photographer of some T5s and likely this mystery set.
Pinkerton Lord front emboss.jpg