Do listen server using Steam always have a region lock, or just the testAppID (Spacewar)?

I am working on game that utilizes Steam sessions, one player hosts a server and everyone else joins, and I had issues with players from different regions trying to play together while using the Spacewar (480) test ID, will this happen with a real ID aswell?

Hey @yeswecamp , did you ever find out or does anyone have an answer for this question?
Is there any way to get around the region lock for “Spacewar”?

Update for anyone wondering: Spacewar is indeed region locked, a friend tried to connect to my lobby with an active VPN and even from a different city within Germany he was not able to join my session

EDIT: Can be fixed via setting the download region in steam to the same city and then restarting steam.