645. Where by virtue of the death of an individual a taxpayer acquires a property that is an interest in a partnership to which, immediately before the individual’s death, sections 639 to 644 applied:(a) the taxpayer is deemed to acquire a right to receive partnership property and not to acquire an interest in the partnership;
(b) the taxpayer is deemed to acquire the right referred to in paragraph a at a cost equal to the amount deemed to be the proceeds of the disposition of the interest in the partnership to the deceased individual under section 436 or subparagraph a of the first paragraph of section 440; and
(c) section 254 does not apply to such right.