The M38 is really an M91/59. Much rarer than the Yugo M48 Mauser.
To collect, the M91/59 Mosin Nagant is the right choice.
To hunt, the M48 Mauser.
Don't try to "improve" either rifle, if you are concerned about value, they are worth more in the current condition than bubba-izing. If you want or need a gun to hunt with, get a gun for hunting and you'll be happier.