I am new here and wanted to ask a clarifying question: I have a Montana 3400rl and it looks like I have a pin extension on it. In all the photos I have seen of others, it appears I have one. I don'...
Just remember that an extended pin box will not allow you to jackknife the trailer anywhere near 90°. It gets you more angle, but not really very much more.
Only a slider, either a sliding hitch or a sliding pin, any of the various designs, will get you a 90° jackknife on a short bed truck.
Totally your decision on how much angle you can live with.