Thanks for the vid, I'll catch the audio at home tonight. It is a very cool working piece to have.
Keep an eye on the rubber bumper they use to attach the hitch to the arm. That stuff ages and can come apart. I suspect it will be in good shape given the rest of the condition. If it ever does fail I imagine you will have some options to convert it to a different hitch.
Do at least cover the trailer for storage. I'd hate to see that fabric deteriorate from UV light. You'd definitely have to commission something custom to replace it if it fails. Although, it looks to be pretty sturdy fabric. Can you tell if it is cordura or other?
I'm impressed with the trailer, a very unique find.
PS I like your bike setup too. Funky rims.