Add my name to the column under Russntustin in that I agree that there is a lot of character in the old paint.
Covering it with clear will only look like what you have done; sprayed a clear coat over the old paint and rust. The clear will be very hard to get to look even halfway decent and will only make the surface shiny...including the rust nubs and dings.
I would suggest that you just buff it out some and you can put a coat of wax right over the rust as long as it's not loose. Wax will cover and stop the rust for the time being. Also, I have seen old finishes that were "shot" with WD40 and rubbed with a rag that look pretty amazing. The oil will bring up the old paint color and also knock down the surface rust.
I like the original unrestored look personally, but each person has their own likes. Lots of repainted trucks around, but there are darn few with original paint and to that end, your truck has a lot of character until it is painted.
Just one man's opinion.
