It should say Philadelphia
Arms Co. on the rib. If it says Philadelphia
Gun Co. on the gun it is a cheap "trade brand" gun hawked at one time by, I think, E.K. Tryon.
See
The Double Gun Journal, Volume Thirteen, Issue 4, and check this out --
http://www.foxcollectors.com/ah_fox/content/philadelphia_arms.htmlHow about some pictures of the gun? Grade? Barrel lengths? Grip style? I don't have 1199 on my list of observed specimens. My list is a lot longer now than when Mike wrote his book!!
Of every wrong thing he wrote in the book, that bit about early Sterlingworths possibly being made from Philadelphia Arms Co. frames is the worst.