For the average Joe, changing out the gauge cluster will just result in cracked plastic, missing clips, and potentially a worse-off cluster than when he started. I don't put much faith in those oil psi gauges anyway. Not all vehicles have them, but they do have a low oil psi warning light. The gauge is useless as far as I'm concerned. It's just something else to malfunction. If his Avalanche didn't have it, the OP wouldn't have this "problem."
My advice is to just ignore it.
My advice is to just ignore it.