Frameless variations are made just with gray border as is and non-frameless are borderized in the Refogerator tool. Some people don't like having this darkening frame and some use other tools to borderize icons, making it thicker, thinner or darker, at least some commissioners ask me to do that.
Concerning UPG, ATT and SSC I just didn't know it shouldn't have the BTN frame, didn't notice at all. Thanks for telling me. I will try to clean the stuff in other bundles as well.