Default Gt-i9195 & gt-i9190 & sch-r890

I see apps and mods for the GT-I9195 & GT-I9190, but not the SCH-R890 model? Is my phone one of these GT-I9195 & GT-I9190 models or is SCH-R890 a different model? I go through US cellular and that is my model number. I was wondering what the difference is between them and why US cellular seems to carry a different model than most people have.