This issue has variants.
The on-sale date is the publication date reported in the U. S. Copyright Office filing.
Letters page letter from Peter Sanderson.
Sources for identification of colorist are The Marvel Comics Index (Olshevsky 1981), The Official Marvel Index to the X-Men (Olshevsky 1988), The Official Marvel Index to the X-Men (Ward 1994), and Official Index to the Marvel Universe (Vandal et al. 2009). GCD’s previous colors credit was to Michele [sic] Wrightson.