Did a bit of googling and wikipedia, closest I could find in Wisconsin with those letters was Sauk County, probably wrong though, can't be sure without the rest of the rear shot, or the person who took the photo clarifying lol.
Also sad to see this go, I'm from Australia so don't see these ladies first hand, but they are in a lot of shows I watch and I love seeing them, use them over most any car in LCPD:FR too.
Regards,
AussieMerc.