I remembered hearing about some of the Model 5s in Indianapolis's original system being HOR Sirodrones a few years back and decided to do a bit of research. There is a map of the original system online, so I looked at all of the Model 5 locations on the map, and then looked them up on Street View and went back to 2007 (before the system was updated). A couple of the sirens were either not visible from Street View or had already been removed prior to the earliest data available, but here are the ones that I found:
8925 S. Illinois St
6900 Aaron Allen Way
7170 Crawfordsville Rd
3401 10th St
3600 E Michigan St
I will update this if I find anything else.
Indianapolis, IN native. Currently pursuing a major in Homeland Security with a minor in Disaster Management from Eastern Kentucky University.