[bigblockv6]

Wiki doesn't have the information on GMC trucks correct, it seems more Chevrolet biased to begin with. The Sierra and Sierra Grande trim packages were first introduced for the 1969 model year, the V6 was still available that year in pickups for the last time and only in 305 version. 67-68 still offered both the 305 and 351 V6 options, coil rear springs were reintroduced in the 69 model and of course that was a telltale sign that more GMC trucks were being assembled alongside Chevrolet trucks. To DAC you are right the Jimmy was introduced in 1970, never carried the K5 designation either in fact early promotional photos show the typical fender emblem used from 68-72 designating the Jimmy as a 1500 series.