You can block after either hand or machine washing. Superwash will block I think but blocking usually doesn't last past the next wash.
Remember that socks are stretched when on the foot a bit like blocking does, the first wash may also even out the stitches/relax the fabric (beside any blocking effects). I say wash it and see how you like it. If you don't like the result, block it, and in future, if it reverts, block it every time (if you want).
You can buy or make sock blockers , easier than fiddling with pins or whatever.