This "AN-2" was indeed something different altogether - it was a PZL-built AN-2, operated by Northrop in the early eighties and named "Linen Butterfly". The civil registration was N22AN and the MSN was 1G142-35.
The story (and I can't vouch for it's accuracy) is that there was concern that the North Koreans were using (or would use) AN-2s to infiltrate Special Ops Teams and supplies into South Korea. Testing was done using N22AN as a target with Marine Corps OV-10Ds at Camp Pendleton as interceptors (recall that the OV-10D was FLIR and gun-equipped and could carry Sidewinders). Interestingly, the China Lake Alumni site has an image of N22AN at Armitage Field, so it is possible that missions were flown in the China Lake complex.
N22AN was also displayed at some of the Southern California airshows at the time including some of the Hawthorne Air Faires. Note that a different AN-2, now registered N22AN, is now on display at the March Field Museum - it is not the same aircraft.
HTH!