Correctly or no, at first sight I would say MAL-uck, due to the tendency of Gaelic, like English, to have the emphasis on the first syllable, for unstressed vowels to schwa, and for final stops to devoice (the latter heard in American Black English cf "KEE-ut" for "kid").
Now, we hear emphasis being put on the second syllable of many Gaelic two-syllable place-names and personal names, but I believe this is the result of the name being a compound. For all I know Mallaig is one of these.
Proud Mountaineer from the Highlands of West Virginia; son of the Revolution and Civil War; first Europeans on the Guyandotte
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