Details:
Catalysis of the reaction: S-adenosyl-L-methionine + (histone H3)-arginine (position 2) = S-adenosyl-L-homocysteine + (histone H3)-N-methyl-arginine (position 2). This reaction is the addition of a methyl group to arginine at position 2 of histone H3. [EC:2.1.1.125, GOC:mah, PMID:17898714]