That much I assumed as well. But with these alarm units I only know that it has a battery port on the board, and that is that. No info is obviously shown on the board about the charge current and how intelligently it goes about charging or protecting the battery.
Assumption 1: All alarm panels use stock standard SLA batteries.
A bit of googling tells me that SLA has typical absorption voltage range (charge rate?):
14.2 to 14.7 volts; typical float voltage range 13.1 to 13.4 volts, whereas AGM,
14.2 to 14.5 volts; typical float voltage range 13.2 to 13.5 volts.
Assumption 2: The panel will assume SLA and "charge" (might be using the wrong term here) the AGM between 14.2 to 14.7 volts and keep it floating at around 13.4 volts max.
So the charging rate is at the maximum, only 0.2 volts too high, but the float range seems ok? I do not see anything adverse happening here?
When my 7ah goes bust, I intend to put at least a 9Ah in there. AGM is still Lead Acid chemistry and I seriously doubt that the alarm circuit charges at high current or discharges at high current. You should be fine.