According to EnderIO not so, maybe they aren’t linking in the forge dictionary? Either way a recipe of 3 obsidian steel blocks on 4 dark steel ingots won’t make an anvil and thats what 9 dark steel ingots makes.
Perhaps they aren’t registered together?
The recipe in NEI:
EDIT
Interestingly you can use obsidian steel ingots in the base of the anvil, just not the blocks themselves.