Yes, you are correct. The Taurus lock system holds the mainspring housing in place even though the pin is removed. The system has tiny little ball bearing detent and springs so if you want to retain the lock I don't recommend removing it because it is nearly impossible to put back together.
I actually removed the lock system from one of my 92s and tapped the hole and filled it with an allen screw after discovering the impossibility of replacing the lock parts. No problem for me but sure it would hurt resale value.