re:correct, to an extent
you are correct, to an extent. You are safe in the sense that he can't use VNC to access you machine, but there are other ways to gain access to a machine...but yes, because you don't have VNC installed, then he cannot gain access to your machine through VNC
"Computers are one per cent inspiration and ninety-nine per cent perspiration. Accordingly, a 'computer' is often merely a talented machine who has done all of its homework."
-Thomas Edison, Modern Day.