I remember those! Also for cheap, close pins and base ball card to have the motor sound along with the siren.
I'd heard the sound of about 50 Harleys under the over head Verrazano–Narrows Bridge on the Staton Island side of the Hudson, I was waiting for the ferry to Manhattan while back in the late 70's. It was the 5 Boro Bicycle Ride of about 75 miles through out the city with about 10,000 riding. Freeways closed off for bikes at locations and the lower section of the Bridge on the South bound direction was close for bikes only for a while. The police motorcycles echoing so loud with that nothing else could be heard. I could have had the siren you have and I don't think anyone would have noticed.
It was also fun to see the folks that were on the subway that day, there were a lot of extras hoping to be called on the set of the movie being filmed that same day, I think in Central Park for the Movie Hair.
MT