Haven't seen a 7K tach in a Challenger. It wasn't by chance a Canadian car (metric) was it?
BTW, a build date of 2-70 is not really an "early" build date. That is actually during the second half of the model year production run. 1970 model year production started in late July or 1st of August 1969 and then ended around the first part of July 1970.
My '70 RT/SE was built the first week of September 1969, much earlier than the one you are talking about. Mine also has the 8K tach and column shift as well.