If you work for the post office, you're a civil servant. The Civil Rights movement focused on the notion that all American citizens were entitled to the same basic civil liberties.
There is also time limit to consider for sending the amended returns, and it is generally three years from the time you filed the returns or two years after the tax payment (whichever is later). If you plan to amend more than one tax return, you have to file separate 1040X for every one you want to change.
You should be filing your tax returns when they are due, the IRS does not allow anyone up to two years without imposing a penalty. If you are due a refund there is no penalty for filing a late Federal return, but you have to file your return within 3 years of the original filing date of the return to claim a refund.