Offhand I was going to say 1968, but after ponderation decided that must have been cars only that year.
I guess they waited until 1970 for the trucks. I know my 68 F-250 doesn't have em.
For cars, side marker lights came in 1968.
1968 F-250 / 300 six / T-18
Dana 60 - 4.10 Limited Slip