Mark the subject of ribs seems to be a study in its self. We have documented rib use by year of manufacture, and have yet to establish any logical pattern use , prior to what I would call the typical 4 wire patterns, most often used on latter barrels.
I would assume that Parker purchased steel for ribs, from the same suppliers that furnished tubes. Many of the patterns match. Some of the patterns are way out in left field. No rhyme or reason.
Plain steel rib materials were more readily available, which is why we believe that your barrels may of been produced by Parker.

Brad

could that be a seam in the middle barrel picture?

Calvin, that mark is where the steel forend tip rests.

I wonder if Parker stockpiled individual tubes and as orders came in selected two and put sets together thus the mismatched patterns. I have a 16ga GH from the early 1900's with mismatched damascuss tubes.

The early twist and Laminated steel barrels are among the most mismatched tubes. I don't know what criteria were used in selecting or matching tubes.
Damascus barrels are a lot closer, but still show anomilies and changes within each tube.

I would think that because composite barrels were basically hand made that there would be variations constantly. I bet that if we examined barrel tubes very closely that no two were exactly alike. But unfortunately the criteria for putting together"matched sets" is lost to time.

Awesome pics at the top Brad. I'm going to have to make a trip across the state to your shop while in Michigan some November. I thought about doing it this last trip so I could have you bend the stock on my Daly, but didn't find the time. I'll make it sometime.

I would imagine that with those early and not high-grade guns they used whatever barrels they had laying there that would work; if they had some that matched, fine, if not, fine also... just getterdone and on the rack.....