Tubular tires don't have a bead, so they don't generally (ever?) have a bead seat diameter listed... although places that sell them will sometimes give it as an equivalence guide.
Continental does make 650c size tubulars, and they label them 26".
This kind of questions pops up in here every few months with the OP sure they have something other than regular 700c equivalent size, but they don't.
700c tubulars fit just fine on 700c clincher rims, so if you have a spare wheel around you can prove it to yourself.