Look at the Mosin Nagant Information Pages on this site. About everything a beginner needs to know is listed there. Just scan through the links on the left of the page. Start in the bottom section. As you study this, you will learn more of this rifle.
I can't tell but it appears to be a 1923-1926 Izhevsk (city where manufactured). In all likelihood, this rifle is also an ex Dragoon. What is a Dragoon? See the information pages

The rifle is also in the appropriate pre war stock.
Take an old rag and wipe off as much of the grease (yes grease... the commies didn't have cosmoline) before you start with the mineral spirits. You will find that the mineral spirits don't remove all traces on the metal. If after using the mineral spirits, you wet a patch with Hoppes, more will come off. The mineral spirits are excellent for removing much of the grease on the stock - inside and out. First, as before, wipe off the excess before applying the mineral spirts - just not as messy... The MS will literally melt the grease and not harm the metal or wood finish.
Good luck and Contrats on a nice rifle
