Nice one. One could also cite the Harbaughs, since they are also on their first HC jobs, like Andy R.
Basically, one faces the same problem when picking a new HC. Either you go with someone with HC experience, who has most certainly been fired before, and hope you get Marv Levy rather than John Rauch or Dick Jauron or Chan Gailey; or you hire an up-and-coming coordinator who is looking for his first big shot, and hope you get Mike Tomlin and not Gregg Williams or Charlie Weiss; or you hire a successful college HC looking to move up and hope you get Jim Harbaugh and not Lou Holtz or Steve Spurrier....
Any way you slice it, there are no guarantees.