Doctor says they’ll cover the cost if my insurance denies- is this too good to be true?

I have United Health Care (primary) and UMR (secondary) and am scheduled to have a colonoscopy and endoscopy on tuesday. My insurance company has told me that I need prior authorization. I’ve been trying to confirm with the doctor’s office that they’ve gotten prior authorization and someone from their insurance department finally got in contact with me and said because the facility is new they can’t do prior authorization, but I won’t be charged anything if the claim is denied for no prior authorization. Additionally, she said the facility was out of network for my insurance (which I was unaware of, as the office where I’m having the procedure done is listed as in network) but they’ll charge me in-network rates. She did confirm all this in an email so I have it in writing. I don’t know much about health insurance, but this seems very strange to me. Is this a normal plausible/thing for a doctor’s office to do? I feel like there’s some weird catch and I’m going to be charged the full amount. I have until about 4pm today to cancel/reschedule and I’m trying to figure out if I should. If anyone has any input on the situation, I would appreciate it.

Also I’m 23, lives in VA but the doctors office is located in MD, and my gross income is 40,000