26 C.F.R. § 25.2702-7
Except as provided in this section, §§ 25.2702-1 through 25.2702-6 apply as of January 28, 1992. With respect to transfers to which section 2702 applied made prior to January 28, 1992, taxpayers may rely on any reasonable interpretation of the statutory provisions. For these purposes, the provisions of the proposed regulations and the final regulations are considered a reasonable interpretation of the statutory provisions. The fourth through eighth sentences of § 25.2702-5(b)(1) and § 25.2702-5(c)(9) apply with respect to trusts created after May 16, 1996. Section 25.2702-2(a)(5) , the second and third sentences of § 25.2702-2(a)(6) , § 25.2702-3(d)(2) , the first two sentences of § 25.2702-3(d)(4) , the last sentence of § 25.2702-3(e) , Example 5, the last two sentences of § 25.2702-3(e) , Example 6, and § 25.2702-3(e) , Examples 8 and 9, apply for trusts created on or after July 26, 2004. However, the Internal Revenue Service will not challenge any prior application of the changes to Examples 5 and 6 in § 25.2702-3(e) .
26 C.F.R. §25.2702-7