I saw a system in a grocery store that had wall-mount TrueAlert horns and wall-mount TrueAlert strobes mounted next to each other on the ceiling.
I know that Target here has separate horns and strobes. A former store here had separate horns and strobes. This was due to the store only having horns installed in them when they opened in the late 80s. I remember in about 1998 (around the time I got over my initial fear of the alarms), they installed strobes.