they declined minimum bid at T-48 and then offered a cheaper upgrade at check in which I accepted. The reservation still says J however my BP states F but I have not received email confirmation of the change in the ticket. Should I be concerned? My card has been charged.
Your ticket won’t be changed, as upgrades done at check-in/gate are in essence a seat change rather than a ticket change with a corresponding EMD. All of the original provisions of your C ticket remain (luggage allowance for C, mileage earning, etc).