I usually go for Stealth "Stock" on things like this
Meaning if you take a glance at it, you've got a plain old Stock Truck - Nothing to interest a car thief, and a Movie Company might even want to lease it from you to film a Period Piece from the late 80's
But you look a little closer and then you can spot all the custom stuff - Nothing obviously Spackled on with a ton of Bondo, or mismatch items like cab marker lights off a Peterbilt, but you go for subtle and functional like upgrading all the side markers and taillights and license lamps to LED.
And little things like Frenching the base of the radio antenna down into the fender. Wouldn't shave the door handles (electronics fail) or other wild stuff like Chopping the roof or slamming the suspension, because that wrecks the intrinsic value of the truck as a truck - Drive places and haul stuff, reliably.