As they were always (bar very few exceptions) driven cab first, I would see it as the 'front' of the loco.
I know that in the States, they view the cab as the rear, which would come from the steam days I suppose.
That being said, even though the locos are American, when used in Ireland the cab was the 'front' - regardless of what way the controls were laid out.
Way I see it, if you imported a left hand drive car from the States to Ireland, you wouldn't go driving it on the right hand side of the road, even though the steering wheel was laid out with that in mind!
But do whatever you want - especially if you have or had Yank layouts, and are used to that way of thinking front v rear!