If you did not live in the home as your main home for any period of time in 2009 or later, you have a period of "unqualified use" and some of your gain is taxable despite the exclusion. Or, if you ever used part of the home for business (rental, home office) and took or could have taken depreciation, then part of your gain may be taxable.
However, barring those circumstances, if you qualify for the exclusion, the exclusion is larger than your gain under any scenario, and you would only need to report the sale if you get a 1099-S. You would have to ask your closing agents whether issuing the 1099-S is common in your real estate market. It may not be, especially for residential real estate. (not rentals, not commercial, etc.)
Note that if audited, the IRS only has to award any basis you can prove. But if you have an estimate of the FMV from other resources (Zillow, etc.) you might take a chance on using that as your basis, and only paying for the retroactive appraisal if you are audited. You don't send any appraisals or proof of basis with your tax return, even if you report the sale on schedule D. But keep copies of all your records for at least 6 years after the sale.
