I started playing a few LAN games with a friend of mine, but i only have one copy of the game so in order to play COH LAN style, I can't update because it would require me to login to my COH account and the serial number would be used twice if we both logged in, which I'm sure would ring some bells somewhere. Also I don't recal the LAN option being present in the revamped and updated menus of the most recent COH versions. Is there any way I can go around this problem? Appreciate any feedback.
 
Cheers

You can't patch it past a certain point, as they decided eventually to become very DRM-driven.  It sucks, but it's something you've gotta deal with. 
 
As for the LAN play, I have not played the game past the pre-DRM patching, solely because I always play it LAN.  Sorry that I can't offer any help or advice on how to handle this.