This is very interesting!!
To me it looks like these odd markings are under the the Piedmont back. I may be wrong, but I think these markings may have been on the sheet first?
I guess this can be a fun project to focus on, to see if we can find out what else the ALC was printing during this time frame, and try to match them up!!
Cool thread Chris. Congrats on the Griffith Johnny!! Nice
Sincerely, Clayton