"Interesting info from the bandaged up guy about them farming out policys on old stuff . I will ask my agent ."
What your agent should tell you is that it varies state by state. What they do in WI may be, and most likely is, different than in MI, for example.
State Farm is an insurance company ... an insurer. Hagerty is an agent.
Hagerty does not "insure" anything. They place the insurance with an insurance company, and who they use may also vary state by state. State Farm may or may not insure antique cars themselves depending on the state.
Keep in mind that your State Farm agent most likely deals with insurance in one state only ... and you may be the only antique car client he has.
He is probably taking excellent care of you ... but he really doesn't have to know what's going on in Arizona, Florida, California, etc. to be a great agent in Wisconsin.
For fun, take out your antique car policy and see if you can find any "restrictions" in it. Look for anything about "miles allowed per year" or "must be kept in a locked garage" or "NO pleasure driving" ... as stated by one poster
Lots of folks post on these insurance questions. Nobody does any real checking or research.