Thanks for the word of caution!!
As far as the check valves go... The folks at keg connection couldn't have been more helpful. It seems they got a bad batch of them and I (and, I'm assuming wbartoli as well) had the bad luck of falling in the window when they were going out unnoticed. Sounds like we both have replacements on the way.
That said... Any tricks in replacing them? As guessed, this is my first time kegging. Good news is that I was able to clean and sanitize the kegs and rack my anxiously awaiting beer into one, get it in the keezer, and hit it with enough c02 to make me feel comfortable.