I'll just echo a few things. First off, welcome and I hope you find reasons to stay and enjoy this forum. That old girl in the pic is a nice example of an m44. Remember these are not sporting rifles, but military weapons that may very well have served in combat. It's a 53, so those dents, scratches etc most likely are the result of training incidents but also may well have been from some low-level conflict somewhere in the world. This is a part of history, which we as collectors are trying to preserve so that others may be able to handle and experience these fine weapons. Once you start to make them "fine-looking" again, you erase that history and it becomes just another rifle. The non-matching parts are normal for this weapon, as the soviets would repeatedly re-furbish them at various arsenals with no regard for keeping like numbers together. Or, they would strike out a non-matching number and stamp or etch in a matching number (forced-matched). They would even overstamp dates on the barrel or swap out receivers from round to earlier hex style (I understand the Finnish Army snipers use rifles with m91 receivers that may be over 100 yrs old). The advice given to you by the more senior members is good advice: use a scope mount that replaces the rear sight and get a long-eye relief scope.It's actually not in great shape. Look at the barrel itself and the stock and you will see what I'm talking about. I was given the gun a few years back and I just shot it for the first time about 2 months ago. I'm hooked. Recoil to me is minimal, caused in part I think because it's a carbine (certainly less than my 12ga). I digress, however. As a collector's piece I find it lacking due to condition and non matching parts. As a functional rifle I find it top notch (not a single jam yet....over 50 rounds have been put through it since I've owned it, excellent accuracy) but needing some streamlining and upgrading. Just my opinion. If someone has a serious problem with me restocking and scoping it out for whatever reason, let me know.
It's your rifle and you can do what you wish with it, but just keep these thoughts in mind first.
BTW, speaking as an army veteran, that tactical sling looks cool, but slings collect mud and dirt; those 4 rounds will need to be wiped down prior to loading them. Not a good idea in a fire fight.