I am a bit of a purist about leaving mil-surp the way it was issued.
Mostly because Bubba has gotten to so many of them already and sporterized most.
Nowadays making a sporter out of an old mil-surp hurts the value of the gun.
The reality show American Guns recently took an M-1898 Krag-Jorgenson rifle, cut down the barrel, drilled and tapped it for a scope and put a black polymer stock on it. They only charged the customer $2,500 to make his $1,500 heirloom into a $400 hunting rifle. To be fair the proprietor warned the customer, but for $2,500 he could have had a pre-bubba'd gun modified and preserved some history.
When I started looking around to see how the customer had affected the value of his grandfather's gun I looked hard at a few of the bubba guns. There's some incredible craftsmanship on display. Many of these guns were converted with skill and care and are actually very nicely done.
The problem is when the government unloaded them to the surplus market, they sold at less than scrap value so there was no reason to preserve them. I am willing to bet that nearly all of them died of neglect forgotten in the back of the closet slowly rusting solid.
The same thing is kind of going on with Mosin-Nagants. Some pretty nice ones are out there for less than $200. Lots of them are being bubba'd. Some are even being converted to sporting configurations with a great deal of skill. And in fifty years, those guns are going still be worth $200 and unmodified guns might be worth a lot more.
My SMLE is such a case. I paid $70 for Vanessa. She's worth $300-800 now and it's only been 15 years.
With all that said, it's YOUR gun, do what you want. It's prudent, though, to find out what it's worth unchanged, selling it intact could pay for a new gun that's already how you want it.