Noob question, but I couldn't find a FAQ or overview post:

I'm flying my first flight as a US elite (Gold Preferred) in about 10 years on Saturday at 7:15AM (MCI-CLT).

Shortly after 7:15AM, I was expecting an email telling me whether or not I'd been upgraded. The flight has "First Medium" award seats available, so I was expecting the email to say that an upgrade isn't available.

At 1:10PM EST, I board CLT-PHL - a flight that has "First Low" award seats available. So I'm crossing my fingers here that in 36 minutes I will be upgraded.

(If there's an easy/free way to directly look at 'O' inventory on US, I'm not award of it. I've just seen people use "First Low" award availability as somewhat of a proxy for it, if it's not the exact same bucket.

My US account has the correct email and I receive emails from them all the time.

Is my timing right? Should I be calling them directly? Not looking for a rule to get overridden but I'm concerned that I haven't received an email already - even if it's just to say "Sorry, no upgrade inventory is available."