It looks like 'Philadelphia' predates 1904, and was probably bred prior to this catalog offering from the first quarter of 1903...

New American Crimson Rambler.
Philadelphia.

This new variety is a cross between the Crimson Rambler and the Hybrid Perpetual Rose, Victor Hugo. It originated with the successful hybridizer, Dr. Van Fleet, who says that he considers it the best and most valuable new rose he has yet produced.

The Philadelphia Crimson Rambler differs from the old variety in being of a deeper, brighter and more intense color and perfectly double to the centre, and while it is not expected to supercede the old favorite Crimson Rambler, it will prove a valuable addition to our list of climbing roses.

from Dreer's Quarterly Wholesale Price List, January - March, 1903, p.39
HENRY A. DREER, 714 Chestnut St., Philadelphia.
http://www.biodiversitylibrary.org/item/149298#page/45/mode/1up