Yes, it is recommended that you file an amendment and include the 1099-R. Code G is for a direct rollover but you still need to file the 1099-R on our tax return. Because this was a direct rollover, you should not have any tax implications.
However, Give yourself some time just in case your receive additional tax documents in the next few weeks. I would hold on to the 1099-R and do nothing right now because the IRS 2016 Amended tax forms will not be ready until sometime in February. This will give you some extra time to prepare your amended return in the event you need to make additional changes.