A Russian "letter series" Tula SKS 1956. A letter Д =D in English indicates the 1956 production year. Quite collectible.
The sling as above, unrelated to the carbine.
I know nothing about SKS or translating from Cyrillic to English alphabet - but there have been a number of former military rifles through here that I have bought - what I found - a stamping on a part might identify the origin of that part - but does not necessarily identify the whole rifle - was most all parts swapped out at one time - even barrels - or at least were able to be - either by the original military, or by a subsequent military, or by a civilian after it was surplused. To know for sure, have to look at almost every part to know it belonged with the stamped part when that rifle left that factory - so like USA Model of 1917 - many were "rebuilt" for WWII by USA military - and the re-built parts got a different finish - so might be correct looking part for the made-in-1918 Model of 1917 that you are trying to put together, but is wrong finish on a part - WWI finish or re-build finish - some care about that, some do not.
"Stampings" - is or was an eBay seller - in Poland (?) who would sell almost any stamp that you could imagine - so home guy could "stamp" about anything that he wanted, on about any part. But will be a difference where the stamp is or was applied on the part - if the buyer knows where it "should" be - and is a subtle difference if stamping was applied before or after the part received its finish. So a potential buyer can not always 100% rely on existence of a "stamp" to know that part is an "original", if that is important to the buyer.
There is a front band for a Model of 1917 that is here somewhere - has an "E" where the "E" is supposed to be, a "W" where the "W" is supposed to be and something unreadable where the "R" is supposed to be - and an American Eagle Head inspection stamp - except "E", "W" and "R" were different factories - that original part would have got "one" letter stamp, not all three of them.
There was a Model of 1917 (some people will refer to them as "P-17") that I bought for the action, or maybe I bought it for the bolt - it was being used with a Mauser 98 follower and a Mauser magazine spring - and apparently worked fine like that. There was also a 1895 Chilean Mauser that I bought - but the sear and the trigger had Swede crowns - so likely from a Swede 1896 or perhaps a Swede 1894 - or from Swede military spares - and it worked fine like that. But is those details that make hundreds or thousands dollars difference what buyers like me would pay. There are 80 some parts on a Model of 1917 - do they all match?? I have no idea how many parts are on an SKS - but have to look and inspect each, if you claim it is "all original and all matching" - or find a buyer who will pay as if it is, and neither seller nor buyer knows any different. There is a very finite (small) group of people who I would accept their say so that a rifle is "all original" - because i know they would check and verify each part before they said that - but for most sellers, I would presume they know not much - and therefore I would need to spend a couple hours to dismantle and inspect it myself, before paying multi-thousands of dollars for a mil-surp - or any rifle, really.
The value of the Op's rifle is a bit about what it is, but more about what the seller knows, what the potential buyer knows or cares about, and what price they agree upon.