TigerII
This is a vehicle that just came off an LST, probably, into the waters and unto a beach.
By Urgent Fury All the County Class LSTs used the bow ramp to the shore so as to deliver "dry."
My old ride, LST 1197 Barnstable County doing just that:
It was less complicated than "wet" on/off loading:
Most 'Tracs would show some salt staining once ashore, and they'd get a bit of "stuck-on" crustineess once on dryland. They did not get dusty so much.
Up close, IRL, there would be swirly bits of "damp" where the paint was neither wet nor dry. But, that's a "5-6 foot" detail (call it 2m, about 50-55mm eyebal distance fro a 1/35 model). So, something a person could model, but would likely just look like poor painting skills in model form.
It's like the finicky things like how all the fresh grease from the road wheel hubs can leave a hint of oily black around the centers of the hubs. But, again, that's detail that could be seen as just less-good modeling.
You are on the right track (No Pun Intended) with this one.