11F,
I knew as soon as I wrote that, someone would ding me on it! You are correct in that it is possible to find an unmarked (on the outside) trigger that is genuine Miller. As you pointed out some were shaped and filed in such a way that there was no surface left to support a stamping. If the unit is removed from the gun however you should find patent date stamps and/or other Miller markings inside. There is also the story of the disagreement between Ithaca and Miller wherein some triggers were installed for Ithaca by Miller and were not stamped. If anyone ever has a question on whether their trigger is original Miller work I can usually tell quite easily by looking at the mechanism. Elmer and Howard's work was distinctive.
Best, Dan
