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.
The statute of limitations for refunds of taxes from the IRS is, generally, three years from the original (extended) due date of the return or two years from the date of payment. The return for 2001 was due 4/15/02 or, at the latest, 10/15/02 (if extended).