Thanks! Does anyone know the difference between google cal and the stock cal? ha ha
they both are same but signed differently(moto X cal signed by Motorola and Google cal signed by Google) and build at different changeset.
let me explain. Android has stock calender which anyone can use on android but most OEM will remove it and use their own cal app.
just like calculator, clock etc
what google did was they took the Nexus signed cal app(originally from 4.2.2) and published it to playstore
now when you see an update from playstore it might include 4.3 cal code + some bug fixes
but Motorola took 4.2.2's calender code and signed it instead of using Google signed cal app.
I hope its clear. its kind of simple concept but hard to explain.
Moto X has Android 4.2.2 cal code and signed by Motorola
Google Cal has 4.3 cal code with some improvements and signed by Google.
since they are signed by two, cal from play store wont replace Moto X cal.
on Nexus devices it will replace since both are signed by google.