Yes,there is a auto-lock device upon holstering setting (Yes or No) although cant comfirm how well it works,I don't use a holster.

I have patternlock set up to auto-lock when backlight turns off...I set my top right mute button as a second convenience key to turn the back light off, when I push the mute button patternlock locks my device automatically,I put my phone in pocket w/o holster...no problems what so ever!