Short answer is yes - the crew are aware of who has been op-upped - plus the crew will know via KIS devices etc that you are not eligible to upgrade onboard (either paid or with miles - i.e. you can't be op-upped Y to J then upgrade onboard from J to F).
Miles upgrade (pre-flight) will also show (or they crew will be able to tell you are not on a Rev ticket) as it will show you are not eligible for further upgrade onboard (paid or miles).
Crew will also know (if they choose to look) which kind of a ticket you're on (Flex v Saver etc) as it will again show how many miles / cash you need for onboard upgrade.