Fact #1: Get a
title.
From Michigan Secretary of State Website: "All trailer coaches (e.g., pop-up camper, travel trailer, fifth wheel camper, etc.) are titled and registered regardless of
weight."
Cargo trailers under 2500 pounds in Michigan do not require a title.
Fact #2: I bought my 1977
Trillium 1300 (13 foot like your Boler) in Michigan, and you bet I got a title with the sale.
$6500 is kind of a midpoint price wise. Trailers that need significant work are going to be less (any soft spots in the floor, how does the exterior look, etc). Trailers where everything works: all appliances,
lights, good
battery, and so on are going for more.
The 13 foot
Boler is one of the most desirable vintage FG trailers out there. Very strong following. So even in poor shape someone will want it, but not for $6500. Condition is everything.