Pete, that does look like the same approach as the 4-to-7 adapter, but with no requirement for high ground circuit capacity (no support for brakes) the 4-to-6 version doesn't need to separate out the ground wire, so it's a simple plug-in as far as wiring is concerned. Like the 4-to-7, mounting of the receptacle is still required.
The reason I am guessing that this is really a 7 (not 6) pin plug on the Boler
is that I have never heard of separate turn signals from the factory on a Boler
Kelly, this could be like the bearings: if you're not really sure what the trailer plug is, buy both types of adapter and return the unused on when you get home. I don't know about you, but I'm
certainly not sure which one you are describing, because the 6-pin design isn't hexagonal (round body, the pins for a pentagon instead of a hex because one is in the middle) and the Bargman/RV design doesn't have six pins (although the outer six flat pins do form a hexagon in the round body).
Benny's approach would work, too, but if the Boler
has a cable moulded to the plug and in good condition, I would hate to cut it off for a temporary rigging. On the other hand, it could be a good excuse to put a nice new connector and cable on the trailer later!