Of course it's idealized; very few war photographs of this time were truly candid in the moment. Almost any shot would be posed, maybe based on something the photographer had just seen and then asked the servicemen to repeat, but often going further to stage some things and make it look better/more dramatic/heroic/whatever. It's not really until Vietnam that the journalistic war photographer appeared.
The medal looks like it may be the silver Medal for Courage, a low-level combat award (as these things go), instituted in 1938 and of which probably a million were awarded during the War.* Very little detail in this pic but I think I can make out the angular form of the T-35 tank on it. The early suspension puts it at 1943 or prior. If the photographer wanted to jazz up the picture, he could have pinned the star of the Order of Glory on the kid, that would have been far more impressive.
Yes it's true that if you won a medal during the War, you'd wear the darn thing. It's good for the pride and morale of the recipient and everyone around him; isn't that what medals are for? Whether on retreat at the start, or pushing to Berlin once the tide turned, the war machine was rolling and there was no time to stop. If you think the medal sticks out, what about the photographer standing out in front of the camouflaged observation post, do you think the enemy spotted him? Of course it's posed!
As far as propaganda goes, the USSR were masters, to be sure. However, they had a proud military tradition, and certainly didn't go about inventing heroes for no good merit (they had plenty of actual brave saps to shine up for the masses). Now in the graphic arts, there is a strong showing in poster design. If you're looking for idealized fake heroes made up of composite features, look to the literally millions of posters they plastered all over the land.
* The Red Army apparently had just under 30 million pass though service in the Great Patriotic War, with 9 million or maybe more dying. If a million Bravery medals are given out, that's like one per platoon, including many posthumous awards. In the heady celebration of victory a couple million more were presented after the close of hostilities, recognizing actions that there wasn't enough time to get around to during the peak of the fighting. And the medal remained up until the dissolution of the Soviet Union in '91, culminating in serial number 4,5 million and something.
I like the picture.