I'm sure it can, I would think it's more a function of to what extent your open SIP server supports spitting out a config file specific to the vendor's device - specifically Avaya in this case.
I don't know if you're the Grandstream guy, or what kind of development is needed to make a central system like that spit out a global 46xxsettings.txt that has some config as well as "GET $YOURMACADDR.TXT" and a specific MACADDR.txt, but that'll be the bigger hurdle in having easy peasy provisioning. I'd like to think that by definition, if 3 switches are 'OPEN SIP' compliant, that I'd be able to get most of the features to work the same across them. But, that's implying SIP has a standard!