You know what......! We did have our own call sign on the Ubon Flightline from inception of the "Rat Pack" in mid 68 thru its demise, by virtue of some upper management commander, in '72 or so.
We ID'd as "Rat Pack 1" through "Rat Pack 5" etc., depending on how many Metro Vans were on the flightline. We were the only ones at Ubon using the Rat Pack as our "unofficial nameplate."
All of our trucks were plated with the sign you see in our group photo on my website.
I'm hopeing that this is a call sign that qualifies. Our greeting was "Are you a Rat?"..........answer was........"You bet your Swiss cheese I am!"