MN did in 66 for sure. i own the 66 plate. "S" designated snowmobile.
The 65 plates on Langley's sled appear to be normal plates?
shortly after i believe MN went to the decals.
I always thought Polaris made an arrangement with the State of Minnesota so the two Sledder's wouldn't have any issues about running them across the continent. As you can see there were turn signals, windshield wipers, and a set of headlights added, part of the arrangement.
They did get stopped in Montana, but the Governor let them pass through after a Photo session at the Capital.
Those two are the only sleds I've ever seen with a License Plate on.
The first registrations in Minnesota were a sticker with a set of numbers on each side.
AntiqueSledMan.