Context : Its complete designation, SKS-45, is an initialism for Samozaryadnyj Karabin sistemy Simonova, 1945 (Russian: Самозарядный карабин системы Симонова, 1945; Self-loading Carbine of (the) Simonov system, 1945). 
Question : Which was the official year for the approval of SKS?
1945