Warpaints/skins don't show up on weapons.
master branch.start_tf2.bat (or start_server.bat) with no custom launch options.map command ingame).Team Comtress:

TF2:

Launch options:
Graphics driver: 460.02
DirectX level: 100 (10.0)
CPU model: i7-9700k
This is most likely because the TF2 source dates pre-Jungle Inferno, the update which introduced war paints.
The source pretty much is the Jungle Inferno Update but unfinished, they probably had broken skins while working on the War Paint system.
Most helpful comment
This is most likely because the TF2 source dates pre-Jungle Inferno, the update which introduced war paints.