I have windshield lights that mount right on the rearview mirror area and have their own holder for the new & included rearview mirror. They're legal in two ways:
1.) Not hooked up at all, though you'd probably constantly get pulled over for the police guys to check.
2.) With orange glass/plastic to act as hazard lights.
I just have this sitting, so let me know if you'd like to take it off my hands and legally mount them. And that is a great find! After having my 94 SSEi for over a year, I feel a knot form in my stomach whenever I see one. Never been to jail or anything like that, though.
It looks like it'* well maintained. Whose car is that going to be when you get your Bonneville back?