I have French Canadian Metis grandmothers, but no direct maternal or paternal link - will dna testing recognise the haplogroup?
Since only your two grandmothers are Metis (since, by implication, your two grandfathers are not), your (male line) Y-haplogroup would not come from your Metis ancestors.
Your mtDNA (maternal) haplogroup would come through your mother and her mother, who you indicate was Metis. So this would be a direct all-female line to a Metis ancestor (which would appear to contradict your "no direct link" statement).
There is no single haplogroup associated with Metis people. Since Metis people are a mix of Aboriginal Americans and Europeans, the haplogroups which occur among them could be either Aboriginal or European. Furthermore, most haplogroups are not exclusive to any regional group; they just vary in frequency among different groups. Thus whatever haplogroup your mtDNA was shown by testing would unlikely give a strong indication that it happened to come from Metis ancestors.
However, besides haplogroup DNA testing there is another, broader, kind called autosomal DNA testing. If half your grandparents were Metis, then about half of your DNA comes from them and is "Metis". Some of that would likely show up as Aboriginal in autosomal testing, but there is a chance little would if it happened that your Metis ancestors had predominantly European heritage.