should private and public be in different zone files?

[Patrick Cairpre]

Lets say I have a small network of machines using ips in the private range. 192.xx
And I also have a mail and  web server using regular public ips.
Should these be in separate zone files?
Is it ok to mix public and private addresses in the same zone?
I don't want the outside world to think private ips map to my machines.

I am not sure if bind knows that private ips are private.  
Thanks