Interpreting tagging system

This is not a true timber framing query but I hope some of you involved in historic building may have come across this labeling system and could help explain. I have been hired to rebuild an old log cabin; 12'x12', believed to be from the late 1800's built in SE Kentucky or SW Virginia. It has half dovetail corners and is mostly tulip poplar with some chestnut logs. The logs are tagged with a 2"x2" piece of flashing with marks in the four corners. Upper left is the number 1 and circled; upper right is a L,R or B, lower corners have the same number, 1 on left and 1 on right, up to 5 and 5. Would these labels be applied on the interior or exterior faces, from the top down or bottom up? Any other explanations of the system? I took some photos and could forward them if that will help.
Thanks for a great resource.

I can't help you on the tagging system, but you might try contacting Doug Reed. He is in the directory (and not too far away from you) and has studied log structures extensively