All of the noses on our EMD's were imported from Lagrange and by that time they would have F7/9, or E8/9 noses which were all the same. I have no idea what you mean by the front slope of the nose being laid back more?I know about the reduction in size to fit our loading gauge but the example repaired is not standard and you could hardly expect dies to be cut for a limited demand model.
What actually came from the USA were sets of pressed steel parts which formed the shape of the cab from just below the headlight up to the top of the cab roof and back to the cab doors. These were supplied in symmetrical halves joined in the centre. A construction jig was used both in the USA and in Granville, so the complete nose was put together separate from the locomotive frame.
The Clyde cabs were three inches (75 mm) narrower than the cabs built in the USA, So Clyde cut 1-1/2 inches from the inner edge of each side of the steel pressings. ( I have a copy of a note from Clyde Engineering's files stating that this trimming was to be performed.) The locomotives were six inches lower in height, but I'm not sure where that difference was distributed between the bogie centre height, the height of the frame and the height of the nose itself. But I think the completed noses were a couple of inches lower than those in the USA .
The reduction in width of the nose is most easily seen in the width of the pillar between the two angled cab windows, which is 75mm narrower than that on USA locomotives.
The difference in S317, which should be clear when it is placed next to another S, B or GM, is that the front cab windows are angled backward at the top more than on a standard locomotive. This change occurred when the cab was reconstructed after a collision at Barnawartha (just west of Wodonga).