Hi, I have a Charles Daly 10 ga with Jones underlever with "RS" initials on the left bbl near the rib and no Linder markings. Also in the frame slot are the initials "AH" or "AR." I can't remember how to post a photo but I posted them here a year ago I believe. The SN is 1092.

I also have a 12 ga toplever gun SN 16000 range that has "AK" or "AR" or "AB" on the left bbl near the rib. It also has a partial "13" stamp on the bottom of the bbl that I take to be the rough bore before finishing. The bottom of the right bbl near the rib has what looks to be a "C" or "G" stamp.
The bbl flats are also stamped with what may be an "RL" or "AL" or "HL"
Erick