Yes rare if a Shelby.
@dave the wave spotted a very Shelby-like characteristic used on most all their bikes, including the pre-
Shelby Cycle Co frames 1923 through 1925.
The oversized/straight upper seat stay fender bridge. A fat rolled tube mitered & brazed to the stays. Brian, can you take a pic of the
bottom of this upper seat stay fender bridge to see if there is a straight rolled/butted joint visible on the bottom? Also, look for a small welding "weep hole" on the bottom of the lower top tube near the down tube. If it is there, take a photo.
The 1923-25 Shelby Frame Builders bikes did not sport the flat-sided headset cups that I know of. These came after 25. Not sure these on the OP bike are "flat sided". That badge and rivets sure look untouched to me, but others makers badged "Speedways"? And those truss rods with the bend at the axle hole and early crown/truss support design appear shelby-like but the sprocket no so much...Other Shelby affectionados?
@slick @cds2323 @redline1968 @hoofhearted