I purchased the trailer from Debra in CA. This past weekend I made the trip down and brought it home. If you look at the pics of the 1971 unit here; they made changes in 1972.
They did away with the raised solid top and went with a pop-top. They added ribs lengthwise to the top to give it rigidity, however over time the roof has sagged (no crossway ribs?) The Compact Jr has a sloped roofline to keep it rigid.
So . . .being that the pop-top is gone; my plan will be to add a raised solid roof (not like that ugly thing used on the 71) I will make up a plug, make a mold and use a foam core fiberglass addition.
The shell is very solid. Frame is straight and it tracks behind the Ranger well.