After more sleuthing than I should really admit to, it appears to me that the plate is from the State of Michigan. Not that there is necessarily a connection (it's a heavily populated state), but that's where British Only is located and you'll see a lot of parts on eBay coming out of Michigan. I seem to recall that we have members in Michigan, but (apologies to him/them) can't recall who he/they might be. I am assuming that the left pannier also has the names of states.
The picture isn't the exact plate, but it's the closet I saw that fit the form.
Richard L.
