good thing you got the proper size seatpost in this and that it's a 27.2.
Sure seems like T-Mar has gotten very close to the mark, maybe even hit the bullseye, and that Doug Fattic adds fuel to this fire makes it all the more likely it's a Miele (or built by them for another brand, if they did such).
Did you check in the base of the steerer for "rifling" in that tube?