How to verify I have installed the new patch correctly?

[Huib Versloot]

There is no mechanism to verify that I believe, but there is not much you could have done wrong, just as long as you install on the right drive\path of your game. Default it installs to C:\Matrix Games\John Tiller's Campaign Series.
In game you'll notice that the assault rules are patched and the low supply bug is fixed. That is pretty hard to go unnoticed.