Necessary to Reconfigure New XFree86 If No Changes?

[Bob Perry]

A while ago, I deinstalled XFree86-4.X and installed XFree86 3.X in 
error.  Not sure of the version number of the original 4.X package, but 
I'm currently running FreeBSD 4.7-RELEASE and I installed XFree86-4.X 
when I installed the operating system.  When I discovered the error, I 
deinstalled the 3.X version (before configuring it) and then installed 
the most recent XFree86-4.3.0,1.  I ran startx (without configuring 
anything) and everything seemed fine.

Today, I installed a new mouse (two button w/wheel) but the wheel wasn't 
functioning.  Someone had earlier requested help with a similar problem 
and they were advised to edit their /etc/X11/XF86Config-4 file.  I don't 
have a XF86Config-4 file, just a XF86Config file.  I've made more than 
my share of bone-head moves with FreeBSD and I'm wondering now if should 
have configured XFree86-4.3.0,1.  Is there an obvious way to tell?

Thanks in advance,
Bob Perry