I know of two general books on the Aroostook War. The better of the two (containing quotes and extracts from primary records) is Geraldine Tidd Scott's _Ties of Common Blood_; Bowie, MD: Heritage Books, Inc., 1992.
Ms. Scott used many types of sources to identify units and persons involved in the conflict.
None of the rosters she shows mention a person with a Milan-type surname.
Of course it is possible that she overlooked some surviving records.
On the other hand, all free white able-bodied males aged roughly 16 to 60 (varies by time and place) were expected to be available for County militia duty within the County, although most did not have any active duty service. It could well be that a local fort was garrisoned on a rotating basis during a perceived threat, but that a threat did not materialize in that time and place.
The problem of family stories is one that many of us tangle with. People who tell something long after the facts may be blending a partially recalled story with their own conclusions. If my time machine were working, I could get answers to many questions.
If you want to locate surviving rosters from this time period, a trip to the Maine State Archives in Augusta would be on your to-do list.