As above, I agree, its the meter that deternines the output. Its only a few years ago that meters could be switched from mmg/dl to mml/l ( they stopped the capability when people made errors after switching inadvertently) As long as the meter and strips are available in each country (not all are, even from the big manufacturers )the correct strips will be fine.
I've just moved back from France and have over the years had to buy strips in the UK for several 'French' meters. Now back in the UK, I have two Contour meters, one in mmg/dl originally from France, one in mmol/l from the UK. ( my gp was confused and my new consultant preferred not to have to do division in his head so I got a new one!)
I can use the same pot of strips for either.