I haven't billed for barium swallows, but it looks like the cpt's you have are correct. The 92611 and the 74230 are both indicated for barium swallows. I don't think a modifier is required. The 26 is to indicate professional component but the 74230 description seems to be professional component.
If anyone else has billed these before, please let us know if this isn't correct.
Thanks
Michele