Here is my experience: Picked up a nice set of 40/20/40 OBS buckets with console. Never really thought about the brackets. The new seats came out of a Super Cab, going into a Regular Cab. The seats were the same but the mounting was different. Had to put the new seats on the old bracket which is a full width part that bolts to the same points as the bench seat. Visualize 2 seats and center console go on bracket, then goes in cab as a unit.
So this messed up the plan for the 86 to have a set of OBS 40/20/40. This was resolved by finding a truck with junk seats and getting the mounting, Now I have bolt in OBS seats in the slantnose as well.
Now if we are talking individual bucket seats like a Bronco, that is another issue. I have a 95 F250 SC parts truck with individual buckets if you need me to check anything out.