Iron and mild steel were common in early American sword furbishing, as brass was a less common commodity (indeed a high demand for brass during the 1812 war). As you aptly point out, the hilt stamping is the first thing I noticed weeks ago and shrugged off any real interest. The blade is simply wrong for the timeline as well. There was a fair amount of brass being produced in the Philly area by the early 1800s but not enough for general demand. It is interesting geographically by then that PA makers were hilting some in brass, while Starr and others in CT were using mostly steel and iron.