Looking through many boxes of old family photos I found that there were always an excess of photos from the 1920's and then almost none in the 1930s. Folks had disposable income in the 20's and it dried up in the 30's. I also noticed in the few photos I found from the 30's, faces were a little more glum, clothes looked a little older. All of the "pretty" photos like this were from the 20's - and the early 30's. I think I have seen some photos like this as late a 1930 or 1931 but buy 1932 and later, they usually dry up.
I would say that this photo would be from the late 20's up to 1932. Can you say the dates when these lads were born?