Looking closely at the "G", it seems an accurate enough model, though there us possibly slightly to great a curve on top of the front of the bonnet. But with the windows of that design, it's a G611 he has modelled, not a G601. Thus, as stated above, both the silver and green liveries don't apply.
On a more positive note, I'd say the G611 type, as modelled, is of more use to the modeller as there were more if them, and they were used Ina wider sense, including, of course, passenger workings on the Loughrea branch. Apart from the Newmarket and Banagher goods for a short time only, the G601 trio were only used for shunting, and very little at that.