Generally, if the property is sold within a short period of time after death, the sale prices is typically considered to be the same as the fair market value on the date of death (provided the sale is to an unrelated third party).
You, I believe, are making reference to the alternate valuation date set forth in Section 2032 of the Code which provides for an election by the executor to value estate property as of the date of death or six months thereafter.
The alternate valuation election of Section 2032 applies only if the election would both decrease the value of the estate and decrease the amount of estate tax owed. Since most estates owe no estate tax (i.e., neither file nor owe tax on Form 706), the alternate valuation election does not apply to most estates.
