I would check on it. It would stink to get to the airport and not be able to go anywhere.
I have been jumpseating since 9/11 mostly on NW and DL. The sad fact is that nobody really knows what the official jumpseat rules are from day to day. I've had Delta captains try to tell me I'm not allowed, and I work for a Delta wholly-owned for crying out loud!
The bottom line is it's up to whoever is at the counter and who the captain is that day. If they want you in uniform, and you're not, you're not going anywhere regardless of what the "official" rule is.
And if you go on NW, be ready for a not-so-random search at the gate. Every time I j/s they search me. I finally asked the agent one day and she said it's NW policy to "randomly" search all jumpseaters. It gets old when you do it every day.