Normally a pick-up or 1-Ton did not have them. I believe they were an option only. I'm not sure if you could order them from the factory or not, but you could get them installed by the dealer. Large trucks (2 1/2 Ton and larger) seemed to always have them and I would say that they were standard equipment.
It would be really hard to say if yours are factory or dealer installed or not. The only way to prove if they were owner installed is if they did a poor job and were in the wrong position, but I guess it would be possible for a dealer to do a poor job too.
Bill
