Yea was early, and senior moment (CRS?) was fuzzing the acronym... and it help not that the six different brands I work with all use a similar acronym for same basic system but each have different ways to spell out the full name...
You are correct, and good catch.... the belt actuator is only part of the system and the SRS light could be a lot of things....
I lost the link a while back but there is a Mercedes web site for emergency service folks to access (free for any one) that has excellent advice on how to safely extract someone from any crashed Mercedes vehicle...
They do a very good job of technical info on all of the explosive devices, triggers, and where items are located to disarm....
Most of us do not need this info, but at least I learned about each of the sub systems, how they are triggered, and where to look for the control devices...
If I can ever find the site again I will post a link .....
Not much info there helps with this particular SRS light on problem...
I just wanted to get a caution in that it is a complicated and potentially dangerous system to be DIY troubleshoot and fixing...