Yup. Our company allows captains to sit right seat however; there is only one pilot in command. The captain sitting right seat assumes the role of the First Officer (naturally) but overall the guy sitting in the left seat has the final authority.

A while back an Airline (not going to mention name) had pilots listed as captains but in order to be compensated as such they had to fly x-amount of hours as PIC. The airline would have these pilots fly within 5-10hrs shy of the x-amount hrs needed to get captain pay and have them sit right seat the rest of the month. This of course was before the union.