Yep, that's entirely valid. And in fact a lot of stocks have big relief slots there for the nuts that go onto the screws for holding bipods. So a squared out channel in a fairly hunky fore stock isn't a bad thing.
Where I'd draw the line and make it at least semi rounded is for a light and slim hunting stock. The wood might be getting pretty thin in the "corners" if you shape the forestock to a light and rounded shape.
You know.... even a part time wood worker can use a router. It may be time to buy one along with a few well chosen bits. I've had one for literally 30 years now and I doubt it sees the light of day more than once ever 2 years. But when I need it there isn't any other tool that does the job as well or as easily. So I've never regretted the roughly $150 I spent on it and some bits.