Has the executable been updated from the original one of the boxed copy?
I ask because I am unable to run the game with the default executable. I noticed that the only way I can get the game to run is by using the .exe from the Steam demo. And when I compared the executables, I noticed that the one from the Steam demo has a new field (renderer) at the top of the launcher.
Does the GOG version have the same field?

It has a field marked "3D Card" if that's what you mean.
Screenshot attached.

Yeah, I just checked the regular demo. It seems that the demo has a different executable than the retail one.
"I keep getting a Cmodel:Loadheader bad version number: 10
File model.cpp
Line: 2960
Error."

You may want to try what I did to get it to run. On my system Win XP Sp3, I had to use this patch and install their cutscene.dll as the the original one would lock the game on a black screen. It's not ideal cause to watch the cutscene's it launches a third-party viewer that you pick (i use the default vlc) but all works and the patches other features are nice.
http://www.coopdb.com/modules.php?name=BR2fsaa
Hope this helps.

I know this was posted quite a while ago, but I just wanted to share my appreciation for posting that link. I was having trouble getting the BR2 application to even start, and adding the new dll fixed that problem (then I realized the cinematics weren't working, so I messed around with the settings and got those to work).
So, thanks.