Pat,
If a club retains an architect, they typically have a motive behind his retention.
It's not a spontaneous situation where an architect is lost and randomly drives through the front gate.
The club usually has a concept in mind.
Then, the selection process begins. It can be a short or a lengthy process.
Once selected, in many to most cases, the architect is given a predetermined "mission statement" as opposed to a carte blanche approach where the architect has complete, unrestricted/unrestrained artistic license.
I am aware of some clubs that feel that their course is mediocre at best, and as such, they want it reinvigorated, ergo, an architect is brought in and given ample creative freedom.
Each situation is different, but, you specifically referenced a "classic" golf course.
If the club had made the decision to embark on a "true" or 'pure" restoration, and historic aerial and ground level photos were abundantly available, I could see the project being an "in house" project.
But, I'd still recommend the hiring of an architect for a variety of reasons.