Not for pickups I got some in a while back from Amazon, I have the KNF Neuberger vacuum pump ready to go but haven't yet pulled the trigger on the silicone sheeting for the vacuum press.
The Kydex is bright white with one side shiny and one matte in 12" x 24" sheets. Its only 0.7mm thick so likely too thin for pups (think playing card rigidity and thickness) but if you potted it in it should be plenty tough.
By all accounts it will thermoform like a dream right out of a regular oven.
Right angles can be a challenge but this material should give you a fighting chance!