B&M shift kits

The PK indicates that it was built at the Kokomo plant, which is where they were all built.
The next 7 digits are the assembly number, this will be listed in the appropriate year parts catalog and is used when ordering replacement parts. A number starting with 40 should be from a 76 or 77 trans. That should get you close enough when ordering your B&M kit, as they cover multiple years.