The 81 starfield only sticks out to people like us who have over analyzed the starfields like crazy. To the average viewer, the starfield would only stand out if the size and distribution of the stars is radically different, and the evidence points to them going to great lengths to make the stars appear less congested and slightly bigger than they appeared in Empire so as to better match the look of SW.
You have to figure the original starfield had probably been scrapped after the SW shoot had wrapped. So the Empire starfield is probably all they had at the time. And I don’t think they ever anticipated the intense scrutinizing that is possible today, but not so in the 80s.