Sorry don't get excited, I don't recall working on one either, but just a word of caution I suppose.
You have to consider it's a life safety system, its one thing fumbling though programming on intruder worst case in most instances if something was wrong would be a fail to operate and possibly damage or stolen items, not advised but it's not life.
It depends on if you are just providing operational checks or if your expected to repair faults and re-commissioning, you would only need Level 2 access for the former.
I know you didn't put yourself in this position when sales want to takeover any old tat but it is worth mentioning to them it's kit that none of the engineers know how to use properly, if something needs adjusting.
Your right not everyone knows everything about every piece of kit but this is why companies have a list of preferred kit, try to stick to it and train there engineers on it. Leaves less to go wrong.