only very slightly
T4 and T5 heralds have access to a new treasur class specific to drop sunders
but T1 to T5 all can drop grand charms from their normal TC, and if a grand charm drops, then it can be upgraded to unique.
There's 2x more chance that this will be a gheed instead of a sunder, but still, mf does help a bit (and is your only way to drop a sunder if you don't farm above T3 heralds)
Don't give noobs even more immaterial reasons to stack hundreds of mf...