Alarm question

Bought my used '18 Tundra from CarMax and was under the assumption that it didn't come with the factory alarm(or any alarm) installed.
I keep it parked in the garage so most of the times I leave it unlocked but the other night I had it locked but with the window rolled down. I went to grab something from the truck and since it was locked I reached my hand in the window to manually unlock the door and the alarm went off. I frantically ran inside to grab the keys to turn the alarm off since it was pretty late at night and I know I woke the neighbors.
So this would mean that my truck does have the alarm installed. I just tried to duplicate the scenario by locking the truck with window down and reaching in to unlock but the alarm didn't go off and I was able to manually unlock the truck. It seems like there is a delay where the alarm doesn't actually arm immediately.

My question is this...
Is this a setting that can be configured by teach stream or carista?

 

This was posted in the past, it may work.
https://www.tundras.com/threads/disable-alarm-on-2016-tundra-platinum.90793/#post-2285792

 

Thank you