I think you are heading down quite an interesting rabbit hole with your search I notice that no one has responded to your post on the First Gen Monte Carlo site.
Based on what I know the key is the 7 digit Delco number. That number represents the actual alternator. This would include output, clocking, pulley, and whether or not it is internally regulated.
As you know the K85 was a code for sales orders. I found one post that showed the K85 represented a 37 amp alternator ion a Chey pickup. Those codes were reused from year to year and did not necessarily represent the same option package over the years.
Hope you can find an answer.
