What a pretty little truck!
I've never encountered a sectioned (original) frame (that's not to say that it could never happen). I would concur with the guys who say it's been repaired at some point.
Now that you know that it is, I would verify the integrity of the welds and the fitting (alignment) to make certain it's truly roadworthy. If you have any doubts after inspection you might want to gusset it at the splice with an insert. Other than that - enjoy!
