A complete-shootable Mauser for $350? Why not? See if you can talk him down a little, mostly just so yopu'll pay less.
I've several FNs that I bought as actions for $350.
It would be plenty rifle, or you can modify it later to any of several popular cartridges. I'm a strong fan of controlled-feed rifles, and the only difference here is it MIGHT need a bit of polish around the edges. Good gun!