I have had/have two different manufactures AGM batteries, since 2004. Lifeline (made in USA), and Universal made in China). I have an Iota 55 amp charger, and 130 watts of solar. I have done nothing special in my charging systems. Lifeline changed the charging specs no less than three times when I had the Lifeline.
I will not argue theory, but will argue life experience on this subject. Simply stated, I have experienced no need to differentiate between AGM and Flooded Wet Cell batteries in the charging system.
I will add, you can charge the AGMs at a faster rate than Flooded wet cell batteries, if your charging system is up to the task.
Wayne