If my feeble memory serves, I don't think 476 was ever fitted with power reverse. Both 478 and 473 were, though I recall a discussion that it was removed from 473 before 478. I won't swear to that--maybe Earl or another more in-depth loco historian can shed some light on that.
I posted some time back that my "pet" engine is 493, as it was the first (by about 10 minutes) K-37 that I saw under steam (in Durango in 1967). The second was 497. It saddens me greatly that 493 is rotting away in Silverton. I wonder what kind of shape its boiler and running gear is in. I think it should be at the C&TS as another running K-37 with the 492 and 497--when THAT grand dream comes true!