Perhaps if you had started and titled the thread asking for help for issues getting your Apple TV app to work instead of making "rude" vague nebulous claims of false advertising having nothing to do with your ATV app issues, my "rude" questions about your inconsistent statements wouldnt have bothered you.
As has already been stated, the model letters are meaningless overall, and can be ignored.
It still isnt clear which models you have, and which models you dont - your double response of 4670 and 3810 arent directed at anyone or as a specific quoted response. You then talked about your troubleshooting steps and specifically mentioned a streambar and a Roku TV.
Still not clear which models you have, though all of them (no Roku TV model #) are supported with the Apple TV app.
The correct steps to reinstall an app are:
1) Remove the app (highlight and press the Options (*) button, then remove)
2) Restart the Roku (Settings/System/System restart) <-- MUST DO THIS HERE
3) Reinstall the app