Really? Last I heard was Clinton selling them some techie stuff back in the 90s and helping them work out some bugs in the multi-stage stuff....which was rather unreliable ..... waaaaaaaayyyy after 1971 .......
What you are referring to was the use of the Iridium smart dispenser satellite bus on the long march space launch vehicle (a derivative of the CSS-4) which gave them a leg up on a MIRV'able bus design, but they have had single warhead ICBM's since the early 70's, missiles capable of reaching anywhere in CONUS in the early 80's and have been also launching large satellites since the early 80's.
Seriously, believe me on this, they have had the ability to hit us for over 40 years (west coast) and all of conus for almost 30 years.