All lead acid batteries, including AGMs are subject to sulfation. As the electrolite is fully contained in the matt on AGMs the electrolite is not as subject to stratification, which is the other reason for equalizing a battery.
Regardless of wet cell or AGM, it is preferable minimize sulfation in the first place, rather than equalize the battery after sulfation has occurred. The best way to do this is to have a smart charger that is plugged into shore power whenever they are not in use. This will bring the battery to full charge after each trip, keep them at 100% between trips, and shut the charging completely off when not needed. This is the best thing to do to promote battery life, regardless of battery type.
Leaving batteries in a partial state of discharge between trips (which is common practice for many RV owners),is a large contributor to sulfation, requiring more frequent equalization.
I view equalizing as a controlled frying of a battery. While it will fix the problems of sulfation or stratification, it is not something that should be done too frequently. There is a downside to equalization in that too many of them will shorten the overall life of any battery. "An ounce if prevention is worth a pound of cure."