Not really. The point of black bloc is to make it harder for cops to identify any specific person in the moment. “Grab the one wearing, uh … all black. she just chucked a brick” doesn’t exactly work very well. If they want to go through pictures afterwards and single people out they probably can without much trouble.
Unfun fact: A fed infiltrating some radical group in TERF-Island actually went far enough to have a goddamn kid with one of the members while still being on Police Payroll