I'm not extremely familiar with this, but my experience is that the TL1 connections are still required to authenticate with username and password. CTC does allow multiple logins by the same username. And it does keep track of the IP address of the remote host. So you shouldn't have a problem. If you're worried, you could create separate login accounts for each TL1 "user."
How old? Since you said Cerent, I'm envisioning R2.x . I can't even remember that far back. My guess is that if you're R7.x or higher, you're probably OK.