So, the 469 is one of the original D&M units? If so, if the road number is original, it dates from 1946: so one of the oldest roadswitchers around. Even with the rebuild ("250" engine (?) etc), it's still a historic locomotive.
(Thinking about it as a potential museum exhibit... The long hood may look RS-3-ish, but it still has the narrower RS-2 short hood and doesn't have the RS-3 battery boxes: authentic enough for most!)
(Steinbrenner's book is great: I'm on the wrong continent to consult my copy right now, but it certainly has an amazing amount of detailed information as well as a coherent historical narraqtive to fit the details into!)
(Thanks for answering my stupid questions, SSW9389!)