Need help figuring out the vintage of a Barth. This rig is about 33 feet long, has a tag axle and a "step" on the front of the roof. It has square headlights with the name Barth attached in script at about a 30 degree angle. It is aluminium with a center type door. As it is only visible through a building I can't tell if it is gas or diesel. I saw a few pictures of late 1970's Barths but I can't see one just like it. Does anyone have a source where I can match pictures to engine type or year?
Thanks

Barths were custom made, so anything is possible.

If it has square headlights, it is probably 81 or later. I have seen 80's with round headlights.

If it is a tag, it is probably a P30 gasser with a 454 engine, and mid 80's or earlier.

The step roof went away mid 80's. I have seen 84's with and without.

So you are probably looking at 81 to 86.