Looks so. Another point - can the UTC settings in Whonix be a giveaway?
Tor browser presents UTC anyway. If somehow the Guest time is exposed (if not possible with TBB, then say with FF), this info can be used.
For example, a clearnet site in Russian observes the following:
- User accesses it at hours that makes sense for people in Russian timezone
- User arrives through a Tor exit relay
- Browser exposes the OS timezone is UTC
What’s the likelihood it’s a Whonix user? Similarly for an Australian or Japanese site? or a site that mainly relevant for Pacific time users?