The stickers were quite different between certain platforms. I have KQ3 for IBM/DOS and another for the Tandy Color Computer 3 (TRS-80 variant) and the stickers are quite different. The former is a grey-ish one similar to the one you posted and the CoCo one is a black sticker with yellow writing. Also, 16-colours can fall under the VGA definition. It was probably a technicality loophole to garner more interest. Some of the EGA Sierra drivers are named "EGA/VGA" in the installation programs, IIRC.
The different boxes having different stickers between versions is probably similar to how different versions of Sierra games had different disk colours and stickers. I believe there were 4 or 5 different types of standard Sierra designed disks.
01010100 01101000 01100101 00100000 01100011 01100001 01101011 01100101 00100000 01101001 01110011 00100000 01100001 00100000 01101100 01101001 01100101 00101110