Absolutely. I’ve done it myself, and a fellow I know in Cuba routinely uses artist’s oils for his plastic model airliners. (And spare a thought for Jose and all the other modelers out there who can’t get any of the wonderful stuff that’s available for us wealthy and well located types. You could start with US and other friendly forces in Iraq and Afghanistan, and the locals there too, and people all around the world who would enjoy building a model, or a toy for their kid, or their friend…)
The model I painted with art’s oil color was all gloss black and I used black artist’s color from a tube- probably Grumbacher. This was in 1972, and the paint was probably from 1965, but all I had to do was mix it with thinner until it was a good brushing consistancy and I brushed it on. Even thinned with regular hardware store Paint Thinner it took a long time to dry- the whole point to artist’s oil paint is that it DOES take forever to dry, so the user cna move it around, blend stuff, “work” with it, for hours if not days.
So it was a bit sticky for a while but it dried hard eventually. At brushing consistancy, it wasn’t as fine as dedicat4ed Model Paint, but if its what you’ve got, go for it!