Just my two cents and in no way an expert. I have done some reading on the use of the SU-34 in Syria. My research indicates that in most cases the Fullback flew with 4-6 dumb bombs in the 250 to 500KG range. They did use the KAB 500 smart bombs on a very a limited basis. From an air to air stand point, they didn't carry any air to air missles initially, but did start to carrty them after the Turks shot down the SU-24. Both the R-73 and the R27R being seen in one picture that I found and just the R-73 in another photo.
Nothing diffinative, but I would agree that if you are going with an operational load, less more common.
Joe