Customer is looking for as much authenticity as possible. I was noticing the M has slants on the legs and the K has the join in the center. Just looking for something close. We are not going to reproduce the same sign with raised letters in the above described way, just black vinyl on magnets.
The photo as you have posted appears to be of a film crews "donkey" rig.
A car rigged to carry various camera crews and their equipment to get specific viewing angles onto film to add realism to the finished shots.
The magnetic sign is just that, was most likely hand lettered during the late 1960's when this particular police show was being filmed in and around Los Angleos California. It starred Kent McCord, and Martin Milner {anyone remember Route 66?}.
The "mag in this picture actually covered the "to Protect and to Serve" lettering on a real police car that was pulled into service for the film crews of that time.
Note the unit number peeking out from under the bottom of the magnetic sign.