I remember going shopping with my first wife's father (both of whom are now deceased) back in 1969. I do remember seeing an F-100 Explorere and the Explorer was the top of the line trim level. I do remember that the Explorer had a bed light and a luxurious interior for a truck.
I am almost certain that automatic transmission, power steering, air conditioning and probably a radio (at least an AM/FM radio) were options on any Ford pickup truck. A lot of the Ford F-100 trucks did have the 360 V-8, but this was an option. The standard engine was an inline 6. I don't remember if this 6 was 240 cubic inches or 300 cubic inches. I do know that the 240 was the standard engine in 1965 but a 300 cubic inch 6 could be had as well as several optional V-8 engines.
Back in 1969, pickup trucks were "work trucks" for the most part. The Explorer series was not that popular.
Around 1973 Ford introduced the F-150 series in addition to the F-100. The reason, I've been told, was that at the time, the F-150 was heavy enough not to require unleaded fuel, while the F-100 was light enough that unleaded fuel had to be used by government regulation.
As I remember, the F-100 Explorer my father-in-law checked out was a fleetside (not a fender side) model with a short bed (6 1/2 feet) as opposed to a long bed (8 feet). He did purchase a 1969 Ford F-100 that was not the Explorer model with the 302 V-8 engine and a three speed manual transmission with the Borg-Warner overdrive and the short, fleetside bed. It was a great truck and even though it wasn't the Explorer model, the interior was more luxurious than my 1965 Rambler Classic 550.