That's right, splined steering column appeared in 1970 model year, and black early style steering wheel in 1974. But these are translucent maroon, "desirable" orange steering wheel was only available in 1967 model year.
In order to fit an orange steering wheel on my '75 Export, I built an adapter fairly easily by sacrificing a Renault steerng wheel - any one up to mid-90s will do - and welding a flange on its hub.
Ten years ago our main concern was not to find the orange steering wheel, but to find a way to fit it on a later car!