Turned out great!
I have a M101A2 same frame.
Great purchase price too.
Does it have the A3 axle that raises in the center or A2 that is straight?
Where in Pa are you located?
They are working backwards shackle mount should be to the front of the trailer slider to the rear.
they extend when compressed and are pushing forward when hitting a bump.
Loren85022 Has a great fiberglass utility bed build. Lots of great ideas.
http://forum.expeditionportal.com/threads/120463-Utility-Body-Trailer-Post-Build-Tour