Yes you can do that.
Lead acid is a agm .
But its how its beult.
Lead acid have the plate with liquid of acid and water.
Agm have the same and use glass fibers with it
So the acid and water stay more mix and stay with the plates .
The plates on a agm is thicker.
So it can go lower to a max of 50% of the battery total AH (a lead acid like a start battery are only go low for 20%)
So both use the same mix .