Guys i model GN too.The Proto unit i picked up is running short cab forward i believe it should be long forward.No problem changing engineer around but i am not sure where horn gets relocated too and if the horn on top of proto 20000 GP9 is the correct horn?.If i am to move horn then i should at least put the correct one on.Thanks Steve
Steve - According to Charles and Dorothy Wood's The Great Northern Railway: A Pictorial Study, pages 470-471:
"From the purchase of the first NW-3 in 1939 through the last GP-20 . . . the GN operated the GPs and SDs long nose forward for better crew protection . . . . In the early 1960s . . . the GN began to operate short nose forward, because the increased forward visibility was a greater safety feature for the crew than the protection of the long hood."
Here's a link to all the GN GP-9 photos that rrpicturearchieves has: