I sure hope so, my
greenhouse is a really sad, sad place to be right now.
It depends on the variety, some avocados are more frost tolerant than others.
Here is the more authoritative word than my dim recollection of avocado groves that I have seen hit by frost. And the important advice from
this resource:
No attempt should be made to prune or even assess damage from the frost until spring when new growth appears.
I guess we wait for them to wake up in a few weeks and then we see how bad it was.