Alarm Siren Options

[socket]

Hi all...been searching around for info and came upon this site, so hopefully I can get the help and info I need, it would much appreciated.

I recently became the owner of a '99 SR and need some info on the alarm, namely the siren. It beeps (16 times) on every arm/disarm and after searching the net it seems there is a problem with the back up battery and the siren needs to be replaced. Instead of buying a new one I want to try to find a used repalcement, the part# of the current one is 08192-44810, does anyone know if this is the original part for the 6th gen siren?, or is this from a different gen? I've come across toyota sirens that look the same, even the wiring looks the same, but with a different part#, are toyota sirens interchangable, is there a universal replacement or do I need to keep to matching part#?, if anyone has replaced the siren, is it as easy as swapping them out, do I have to do any thing to the alarm system i.e. resetting it, or will it just work without problem.

Any help advice much appreciated