I don't do "permits".

I've got an engineering report from the late 1980's in the glovebox and have never been asked for it.

Most cops are a lot younger than me and I just baffle them with technical stuff, but as I said, I live in a small town where everyone knows each other and there just isn't any problems. I fixed the local cops' daughters bike a few weeks ago and didn't charge her, so I'm banking a favour or two.