I don't think so. This is the full and exact text from 18 USC Chapter 44, Paragraph 922 (Illegal Acts):
(k) It shall be unlawful for any person knowingly to transport, ship, or receive, in interstate or foreign commerce, any firearm which has had the importer's or manufacturer's serial number removed, obliterated, or altered or to possess or receive any firearm which has had the importer's or manufacturer's serial number removed, obliterated, or altered and has, at any time, been shipped or transported in interstate or foreign commerce.
There are no exceptions stated in the act. "Any firearm" means any firearm (as defined in GCA-68). Unless BATFE has issued later advisory guidance concerning enforcement of the contents of GCA-68 regarding pre-1968 firearms, I think the wording of the statute is clear.