I don't know much about Sears and it would be hard to tell without seeing pictures. However, I have seen oval tubing frames listed as aero that were manufactured in the early 80's . These were made when it was state of the art. The six speed freewheel makes me guess that your bike would be mid 80's or maybe even later. Six speed was state of the art in the late 70's and early 80's. I don't think something with Sears on it would be state of the art so it would probably lag state of the art in time by a few years. It would be easier to guess If one could see the componentry.