The AJ-37 and the AJS-37 are the ground/sea attack variants of the Viggen (with the AJS being newer), and do not have an integrated gun, as well as having very limited A/A capability (RB-24's and RB-05A's - the RB-05A's are meant for A/G, but can do very limited A/A against slow targets). The JA-37 is the fighter variant which has an integrated cannon, and very limited A/G capability (M70 rockets).
You can equip each pylon individually through the Equipment -> Fuel and Stores menu, and you can equip every pylon with rockets other than the outside 2 stations. If you're in the AJ(S)-37 and want cannons as well, you'll need to equip a cannon pod. You can also equip armament on the center station in lieu of a drop tank.
And no problem regarding the help. I've got countless hours flying in and working on this plane, so getting to help others is fun. Hopefully I can carve out some time to finally get that new navigation panel on the right side coded properly - I've been sitting on that for about a year now.