Absorbed Glass Mat
AGM lead acid batteries will say "AGM" or "Absorbed Glass Mat," "sealed regulated valve," "dry cell," "non-spillable," or "valve regulated" on the label. Look at the top of the battery. Liquid lead acid batteries have caps or removable tops unless they say "sealed" on the label.
There were a few of the older MoPar batteries floating around for sale (Ebay) that required the addition of acid and were still dry waiting to be filled. Once you add the acid the battery had to be charged. I sold tons of the AGM batteries and occasionally the acid fill type while working for Harley. Especially the 6v batteries for the old Panheads, knucklehead, and Flathead purists. If you didn't follow the instructions for adding proper level of acid and trickle charging the battery, many times you ruined them.