Police car spotlight

You might try Policecarmodels.com.  It looks like the carry modern stuff only though.

I found this https://www.modelroundup.com/Patrol-Car-Parts-Set-C-p/aoshima-59760.htm  Hope this helps.

You might check Ebay; there used to be quite a few police and fire accessories, though often a bit pricey.

I usually just end up scratch-building mine from odds and ends or parts in my 'spares' box...since online photos are usually plentiful, and it's faster than searching for AM parts. Molotow chrome pens can be used to give a nice shiny finish if needed.