Expect to be given 90 days. Especially in Immigration if it's busy while you are there. 90 is an easier number to write than 180, and the agents want to go as fast as possible. The more tourists they help, the sooner they get out of work and can go home, so for many agents it's about what number they can physically write the fastest, rather than what number of days you are entitled to. There was a mandate earlier in the year that said agents should give 180 to Americans, but the agents have personal discretion and use it. Feel free to ask for 180 days if you can show a return plane ticket with a date on it. If you can't show that then I wouldn't bother to ask for 180 days because you'll just be begging them to question you; in that case I would just get your extension from the downtown office.
You can definitely do that, and shouldn't have any problem. But you can also easily extend your stay by going to the downtown office here, so it might not be worth the hassle. And you might get 180 days from the agent at the airport here, I just don't think you should count on it, it's a crap-shoot.
I can't imagine that they will KNOW that you've applied for an FM3 at a consul. Half the time the computers in the airport are being screwy, so forget that new fangled idea that different offices might talk to each other. And even if they do know, are you doing anything wrong? If it's not ready when you come, then you need to come without and get an FM3 here. Relax. My hubby will be working that day, if he's stationed in T3 that day and if you get in his line you can just tell him to give you 180 days and he'll be nice about it. PM me.
