You are confusing the AWB with the 1986 ban on importation of non-sporting semiautomatic weapons.
The legislation we are concerned with is Title 18, Part I, Chapter 44, Section 922 of the US Code. This is why you hear people talking about "Section 922."
Section 922, part (r) says:
It shall be unlawful for any person to assemble from imported parts any semiautomatic rifle or any shotgun which is identical to any rifle or shotgun prohibited from importation under section 925(d)(3) of this chapter as not being particularly suitable for or readily adaptable to sporting purposes except that this subsection shall not apply to -
(1) the assembly of any such rifle or shotgun for sale or distribution by a licensed manufacturer to the United States or any department or agency thereof or to any State or any department, agency, or political subdivision thereof; or
(2) the assembly of any such rifle or shotgun for the purposes of testing or experimentation authorized by the Attorney General.
Part (v) is the part that bans assault weapons, and reads in part:
(1) It shall be unlawful for a person to manufacture, transfer, or possess a semiautomatic assault weapon.
(2) Paragraph (1) shall not apply to the possession or transfer of any semiautomatic assault weapon otherwise lawfully possessed under Federal law on the date of the enactment of this subsection.
Part (w) applies to high-caps, and the relevant text reads, in part:
(1) Except as provided in paragraph (2), it shall be unlawful for a person to transfer or possess a large capacity ammunition feeding device.
(2) Paragraph (1) shall not apply to the possession or transfer of any large capacity ammunition feeding device otherwise lawfully possessed on or before the date of the enactment of this subsection.
The AWB will presumably sunset in about 9 days, so parts (v) and (w) will simply cease to apply, but that part (r) will stay in effect. WRT that part, the ATF and/or congress came up with the rule requiring a rifle to contain so many US-manufactured parts to define what is "domestic" as opposed to "imported." So, as I understand it, you can put the CAR stock on your poodle-shooter but unless that AK was either assembled before 922(r) was passed, you can't build it, period, unless it has the magic number of domestic parts. If you comply with 922(r), you're good to go, since (v) and (w) will no longer present any limitations on your configuration.
Sorry to be so long-winded, but I wanted to put the actual law out so people can read it if they want to.
I didn't have time to look up the text for the AWB expiring after ten years, but hopefully someone else can post that.