I just picked up an old PFM/United K-28. I want to model 478 as she was in 1950. Most of the changes are obvious, but one has me stumped: This model has a rather large power reverse cylinder under the running board, just forward the cab, engineers side. Was this added after the San Juan was Discontinued? Someone recently posted something about p/rev being added at some point. If so- what was here before? SR