It depends. To clarify, do you mean $12,550 since that is the income threshold? So if all your three W-2's are below $12,500 then you are not required to file an amended return. However, if you withheld any taxes on those additional W-2s it is a good idea to file an amended return since if you are below the $12,500 threshold, it will most likely increase your refund.
Please keep in mind that if you have self-employment income, you are required to file even if your income is below $12,550.
