Post-WW2 the StG44 was continued in production by the East Germans and used by the Czechs and Yugoslavs in the latter case into the 1980s. Not only that, but even the NVA was sent some during the Vietnam War. Since the AK47 wasn't ready and the StG already in production and a known weapon to western nations unlike the AK, given the advantages of the weapon over the variety of SMGs left over from WW2 it is somewhat surprising they didn't get any during the Korean War given that they got so much surplus Soviet equipment.
So what if the Soviets had gifted the North Korean Army with StG44s instead of PPSH-41/43s? Given the limited number of North Korean soldiers and the pretty substantial firepower increase it would mean, not only would it be feasible to do so, but would boost their combat power. Though heavier, it would allow for increased range of engagement, rather than forcing them to close within 100m or less to open fire and within range of effective counter fire (US OR demonstrated that US riflemen could generally only hit the enemy within 100m).
Rather than this being a minor POD, in 1950-51 small arms played a shockingly disproportionate role for both sides during the invasion, with artillery only taking back it's dominant place after the lines stabilized along the parallel after Chinese intervention. US OR demonstrated that and I can share the pdf of the report if anyone is interested, while the book "This Kind of War" covers a lot of the major engagements during the 1950 invasion that show how important small arms were during the critical fights, especially around the Pusan Perimeter when the North Koreans had outrun their support weapons they couldn't manhandle with them (or weren't smashed by airstrikes) while the US was short of everything due to the retreat and state of army supply at the time.
How might this impact US/NATO decisions around small arms? The Com Bloc forces were already decided on the assault rifle concept, they were just waiting for Soviet manufacturing/R&D to catch up to demand, so I only see this being confirmation for them.