In what would be an Ockham's Razor scenario, in that the simplest answer is that it is a quality V-C type frame with what was considered for some reason at the time to be an upper rung tubeset, which I wouldn't define as odd or as a non-original set. Many of the Paris retailer's examples for the period wear Jno. Hy. Andrew Toledo Steel from reasons unknown. The frame is unadorned, unmarked, and along with the tubeset reeks of quality. Might be some maker's mark on the inside of the locks to point to sourcing. I would term it that you have a Belgian Tradegun based on a V-C type platform.

Kind Regards,

Raimey
rse