One thing I noticed in the 1991 catalog, King’s Quest 4 marked as available for the Macintosh, was this actually ever released?
http://www.sierra-collector.com/games/catalogs/9/4.cfm
It was listed as ‘coming soon…’ for most of the 10th anniversary catalogs
http://www.sierra-collector.com/games/catalogs/5/24.cfm
http://www.sierra-collector.com/games/catalogs/6/1.cfm
http://www.sierra-collector.com/games/catalogs/7/1.cfm
http://www.sierra-collector.com/games/catalogs/8/2.cfm
Space Quest III was, but it looks like Police Quest II, and Larry II were not.