Hey guys! Long time no see since I got married

I have a question regarding a reception my H and I have been invited to. (Question at the bottom if you don't feel like reading)
A friend of ours got married this summer... I was invited to the shower they had in the spring. I wasn't able to attend, but my MIL gave the friend a gift from all of us.
They got married that summer, but we were not invited.
Then a few days ago I got a facebook group invitation from his now wife, saying that they were having the reception in December and that I'm (we're?) invited.
I haven't seen this close friend of ours in over a year since he became a member of the wife's church, so I'd really like to see him. My H is refusing to go. I have no idea what to expect, how to dress, given that the invite is on FB. I guess she made the guest list private so I can't tell how many poeple are invited.
She listed their registries on the invite page as well, so I guess they are expecting that people might want to bring a gift? But given all of the above, is it appropriate for me to bring a small gift (since our family already gave one)? I was thinking a cookbook or something.
Help!