Yeah. So it should be the ethernet address of the AP acting as the BDD. I don't believe it augments that MAC any per VLAN. But if you SSH into one AP (unless you know which AP is acting as your BDD then SSH into it).
If not the BDD run this command:
show bonjour status
Look for "My BDD: <IP>"
Then SSH into that BDD IP. This is the IP of the AP that will have the interfaces on the VLANs. Once in that AP, do a:
show interface
This will show you the interface(s) that exist on the AP. If you see eth0, eth0.1, eth0.2, etc., then it does create sub interfaces for each VLAN and you'd need to reserve a unique MAC per VLAN.
Note you probably want to set priority for this AP to always be your BDD if you reserve IP for it in your DHCP scope. You can edit the AP individually and adjust it's BDD priority value under Optional Settings and Bonjour Gateway Configuration (HM Classic). Higher number takes precedence I believe.
