Should I brown meat for a stew before freezing it?
It might save you a few minutes when you decide to use it. Meat that has been frozen takes a bit longer to brown, since it will exude a bit more moisture.

But it's probably not worth it. Browning meat, then cooling it to freeze, is a huge hassle. Plus, you'll lose the fond on the bottom of your pan (unless you de-glaze and save that too.) That's a huge amount of flavor loss. You might as well just make the stew and freeze that (which is also good).

If you're going to freeze the meat, freeze it in the form that you got it. Defrost carefully (in the fridge, not the counter) and dry it thoroughly (e.g. paper towels) before browning.