Yes, the couplers on the locomotive are at the correct height.
However, it appears the question had to do with the locomotive having couplers at a height that would allow coupling with truck mounted couplers.
So, if a person wants to pull cars with truck mounted couplers then the lower offset couplers will have to be used.
It's all well and good that the couplers are at the correct narrow gauge height but that sure doesn't do any good for being able to use cars with truck mounted couplers.

Pictured is the coupler height of the 2-6-6-2T, as delivered, matched to the kadee height gauge. The couplers, as delivered, match the coupler height of Bachmann's 1:20.3 rolling stock. Bachmann also provides offset couplers with its 1:20.3 rolling stock so those cars can be set up to couple with cars having truck mounted couplers.
One of the "Enthusiastic Children"
JD