Yes, I would recommend Amending your return to include the Form 1099-R even it makes a small difference, just to avoid any IRS notices in future years.
You can click here for instructions on Amending your Tax Return: How to Change a Tax Return You Already Filed.
Note: You should wait until your return is fully processed and you receive your Refund before you file an Amendment. Form 1040-X should be available in mid-February.
