By the way, make sure you stay on top of the situation if it takes longer than a few weeks. Here is my story.
When I got my IR my certificate didn't arrive and I was getting pretty close to the expiration date of my temporary. I contacted the FSDO a few times, left messages, etc, and basically got told to be patient. From the tone of the voice of the person I was speaking to, I was obviously an intense irritant to him. I eventually bypassed the FSDO (Fort Worth office), and spoke to someone in Oklahoma who informed me that there had been a mistake on my application by the DPE (who had accidentally said my checkride was ten times longer than it actually was because of a dot that was upside down), and they had sent it back to the FSDO who in turn were supposed to get hold of the DPE. They claimed they had been unable to contact the DPE (by the way, the FSDO said nothing about this when I called them).
Multiple blame fingers were being pointed in random directions (as is typical in government but that is a side comment), and the net result was I was about to no longer be a pilot. Yes, when you get your temporary certificate apparently if it expires before your final one, you actually lose your previous certificate. I had that lovely bit of information disclosed to me at that point. Wonderful! The person I was talking to in the Oklahoma office said the next process would be to send a new letter to the FSDO requesting a correction to the application (which involved inserting a period in a number or alternatively making sure it was not upside down), the FSDO would then contact the DPE (by mail). I suggested in my most polite voice that perhaps I could contact the DPE directly by phone... Amazingly this had never occurred to them. I got it sorted out in a couple of days.
So the morale of the story is, be especially watchful for periods (dots) that are upside down on your application. The FAA doesn't like that. Also, if it is late and getting uncomfortably close to the expiration of your paper temp certificate, you need to become, shall we say, more unpolite in your demands for satisfaction.
EDIT: Okay, I exaggerate. The dot was not upside down. It was missing. The FAA apparently has concerns about a checkride taking over 10 or 20 hours. They flag that as problematic.
