My experience is the Delta staff will tend to look at your status early on in a conversation. When I turned MM several even offered short congratulations on having made it.

Once I went to a gate in ATL to get on to an earlier flight. A woman was in front of me and asked the same thing. The agent glanced at her current boarding pass and directed her to the customer service area. He glanced at mine and punched a couple of buttons; we exchanged pleasantries as my new boarding card printed.