Fender rive size

I just purchased a 1914 Runabout project. What size and style is the rivet head for the fender brackets? Mine are the four rivet style but the rivets have all been replaced with different carriage bolts. The suppliers list the 14 rivets as “oval head”, is that a truss head? What size is the head? I would prefer to use a bolt instead of trying to smash a rivet but I want the head to look correct. Art

They are Oval Head Rivets. You can buy the rivets and sets at Big Flats Rivet Company in Horseheads, New York. Their phone number is 607-562-3501. Call them and discuss.