Correct, quite common to have two captains together...
After all, captains can be first officers, why not...
Many scenarios are possible...
There may be a check-captain in the right seat, giving training to the other.
That is quite common with all airlines.
Reserve crewmembers. First officer is calling sick.
Crew desk calls reserve first officers, but none available, so they get a captain.
I am a management pilot (captain) as instructor. I often replace first officers.
Many of our 747 first officers were captain 737, they continue wearing 4 stripes.
All our captains AND
first officers are qualified as captain in 747 (same qualification)
So you may also see a first officer in the left seat with us. They are captain qualified in the 747.
We just "trade seats", the captain decides "who flies left seat" going out and coming back...
Now were are getting these 747-400s on the line. I will not fly them.
The normal crew complement is 2 captains + 1 first officer. That is because of length of sectors.
Both captains will occupy pilot seats for takeoff and landing.
The first officer will only occupy a pilot seat in cruise. They are... "cruise first officers".