Amtrak 907’s F end horn was replaced with this shop mutt at some point. It’s all RL bells except the 90s era 3A which has snow cone holes and traces of Charcoal gray (likely from a P40/42 or Dash 8). It kept this horn until scrapping, and was one of about three AEM7s that got replacement horns with CDFs. It sounds very much like an M5 (for a K horn), which was Fred Berry’s goal when retuning the RL K’s around 2010.