Does a regulator prevent battery overcharging?

[RXRZ]

I used to know this, but it's been awhile. I have a 2008 yami 40 4stroke. I bought and installed the yamaha rectifier/regulator inside the cowling. I've had it hooked up to a little battery for a couple years with no problems. I just got a bigger expensive AGM battery. I want to be sure in my assumption that the regulator keeps the battery from overcharging?? Hoping I don't need some kinda external charger box. Thanks.

[boats.net]

Yamaha only recommends a lead acid type starting battery because the others may not be compatable with Yamaha charging system.