Decedent died in 1960s. Artwork passed from Decedent's estate to a testamentary trust which is still in existence.
Executor filed a federal estate tax return in 1960s. In order to confirm stepped-up basis of asset passing from above estate, is it possible to request a copy of the above estate tax return using IRS Form 4506? How likely would the IRS maintain a copy of above estate tax return?
If so, may the current trustee of the above testamentary trust sign the IRS Form 4506, or must the Decedent's estate be reopened in order for an Executor to sign the IRS Form 4506?