Yes, they are simple and rugged, some just on the finished side of crude. But they were intended to survive and function in the hands of peasant conscripts with little or virtually no training.
I'm not sure when they changed over, but I do recall hearing that the original Moisins had sights marked in
arshins, not meters or yards. Without looking it up, I think that arshins are shorter than yards, perhaps 30 inches? It an old Russian measurement (pre soviet union).
Regardless of what the sight is marked in, shooting high is normal for many milsurps of the era. The Swedes taught their troops to aim for the belt buckle, and I'm sure many, if not most European countries did something similar. As others have noted, this increased the odds of a torso hit at unknown, or mis estimated range.
I have a Swede that with the sight all the way down, is dialed in on the 400 yd gong! I could change it, but I don't feel its worth the bother. You can change the front sight, (some people just add a piece of rubber tube over the post), mill down the rear, or just live with it and aim low.
If you want a real project, and are a handloader, you can play with different bullets and velocities until you find the one that shoots where you think it should with the stock sights. If nothing else, you get to shoot a lot,
You can also try the different kinds of surplus ammo, there is a difference between them besides light and heavy ball.