An hour before at that time should be fine at that time of the night. I would just print your gold status from Delta.com if you have a chance. The person checking the priority lane (if it is even open at that time) is really relaxed on who they let through so
I usually carry my old Platinum cards with me when I am traveling with people and just give them the card. Basically the priority line screener just glances at the card and lets you through ... I have never actually been stopped and had my ticket examined.
Good luck on the upgrade too