well, i can only speak from the experience i've had, i have american canteens and have just sold a batch of dutch canteen cups and the items i tried would not pair up, the us canteen wouldnt slide all the way to the bottom of the cup.
++just tried an american canteen dated 1977 in a dutch mug dated 1989, the bottle goes in but is too wide at the shoulders to go all the way in, its stops at the text on the bottle.
i will say, i had too different styles of mug in my batch, one type had got the same style lip as the american type and though it fit onto the bottle, it wouldn't go into the pouch and button up.
better to buy the dutch set which is a US type bottle with a gasket in the lid which is better than US type, or even better still get the 1 litre 58 patt type dutch bottle and mug. both these options fit the dutch mug. the bigger bottle tho wont fit into the american pouch either.