It is indisguishable in a sense that all Tor users share the same exit nodes, so you don't know who that was. However, list of exit nodes is available online a

It is indisguishable in a sense that all Tor users share the same exit nodes, so you don't know who that was. However, list of exit nodes is available online and a lot of of sites auto-block it, because abusers like to use Tor.