Alton Fix sold me an M-4395 at Springfield that still had the original pin. The pin was stuck in it from being mounted on a pole with the ridiculous stacked array in a strain position. This insulator pin came from this pole http://insulators.info/pictures/?id=419693282 . What is interesting is; on the rusted steel portion, bottom left, and not the lead portion, there is cement in the grooves in the pin. The lead threaded portion appears as though the lineman poured hot lead into the threads of the insulator, and then stuck the pin in the molten lead & let it cool. Is the cement from where they smashed the M-3890 off? We shall never know, however it is entirely feasible the M-3890s were in use up until the 1920s, 30's, and 40's.