I have an Isahpore, it shoots decently with the iron sights. I am a big fan of my mil-surp rifles, especially the few I have that are genuine, or even "fake" snipers. I like the tough actions that can take abuse, and all steel and wood components. But I don't think you should put any money into making the Ishapore any kind of precision rifle.
As the supply of mil-surp rifles is drying up, I have stuck to keeping my rifles as-is, and getting an inexpensive sporter rifle when I wanted more accuracy and the ability to add optics. Not that I would ever do it, but just to get a Mauser 98 drilled and tapped, and bolt bent, possibly barrel changed to 30-06 or 308.... that will cost you. For what that price I could buy a used Remington 700, and down the road replace or swap a barrel if it was ever needed, for a moderate sum.
So now, I balance my appreciation of military rifles with the needs of my aging eyes, by seeking out well done sporterized military rifles. I'm not talking about a horribly butchered action that had a scope poorly installed in someone's basement in 1950. There are decent '03's, Mausers, and M1917s that were minimally modified, and got a set of scope rings or peep sights added decades ago. They usually sell for pretty low prices, and you could not pay to have the same work done today for less than several hundred dollars.
You have to check the rifles carefully though. If it looks like a hack job: avoid it, because I have seen home drilled actions that were way off for scope mounts. They are essentially trash. But if the overall job looks like quality work, and still has the original mount on it, you should be in good shape.
I have an M1917 that had the rear sight ears cut off. The original stock was chopped down too. But I am almost tempted to put it back into a military stock, and then keep it as-is. Tough call... it's my money, essentially for cosmetics. But even cut up a bit, that $100 ugly M1917 is one tough, accurate, and reliable rifle. It does not look like much, but it survived the trenches of WW1, and will handle a muddy, snowy, or rainy hunting trip without blinking an eye.