Originally Posted by omario117
Will replacing the messaging app keep the notification icon on the lock screen working, or do I have to keep the Samsung version for this functionality?
It will remove the Samsung messaging icon that notifies you in the middle of the lockscreen. You can however add the AOSP messaging app to the quick launch bar on the bottom of the lockscreen for essentially the same thing and you'll still get the LED notification and notification bar alerts for messages.
You can find that option under Settings/Security/Lock Screen Options/Shortcuts.
My Android Device History
Current: T-Mobile Galaxy S III T999
T-Mobile Galaxy S II T989
T-Mobile Galaxy S Vibrant