No, not yet. It would be best if they are found Not Guilty in military court. If that doesn't work out, and appeals are exhausted, THEN its time to take the pardon request up to the White House.
A pardon assumes guilt but grants forgiveness. I for one don't believe these men are guilty of anything.
The only issue with a "not guilty" verdict is that it is costing the families money to defend their Marines. Hopefully the Defense Funds are now collecting enough funds to offset the costs of these trials.