For Las Vegas, no. The Las Vegas City Police Department and Clark County Sheriff's Department merged into what is now the Las Vegas Metropolitan Police Department in '72. That's why the '74 depicted is tan/white.
Most major cities wouldn't have a car for four years. If there was one, it would have been in a specialized unit, where it wasn't driven much or just driven by one or two people. Changing markings/colors is a huge fiscal and logistical undertaking. My old department had 365 marked cars, just cars, not vans, trucks, bikes, just cars.
We changed graphics in '93 and again in '95, and again in '96 all due to financial considerations. There were so many cars on the street all marked differently it seemed like three seperate departments.
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