After property owner passes, when is basis stepped up?

I have a client who is the sole beneficiary of the estate of her grandmother, who passed away in March 2016. The grandmother owned 1 home (her main home), and it is now part of the estate. My client is the personal representative of the estate, and her attorney has said it's ok for her to sell the home. If the home is sold while it's still part of the estate, the basis has already been stepped up, correct? I'm thinking this is so, but I hate that nagging feeling I'm getting that maybe the basis only gets stepped up once it exits probate and title is transferred to my client, and that maybe she's selling it too soon.

Basis is stepped up on the date of death. There will be no gain if the estate sells the property unless there was appreciation on the property from date of death to the date of sale.

if you sell within 6 [or 9, I forget] months of death, that becomes the basis and the 706 if filed, might have to be amended.

The basis is stepped up as of the date of death, unless the executor elects an alternative valuation date. The election is made on the estate tax return Form 706. If the property is sold or distributed within 6 months of the date of death, the basis is stepped up as of the date of the distribution. TR §20.2032-1