Since there are no images of the C64 release with the part number specified, I did a quick Google search and found this:
The part number listed in the database is there, but that is the former phone number for Microprose. This is corroborated by a search for that number with Microprose and a bunch of old PC magazines listing the address (same as the label) and phone number for the company.
I can totally see how that could be misread as a part number though.