W. Bush's Military Records and Tax Filings

This article off of the AP states that Bush’s Military Payroll Records were inadvertently destroyed.

My question is, wouldn’t his tax filings for those years in question give the substantial proof of payment and would they still be available?

(I’m leaving whether or not they’re in there as irrelevent for the sake of keeping this from getting side-tracked).

In a non-exhaustive search of the IRS website I find reference to the ability to request copies of tax returns from up to ten years previous. By implication that would indicate that tax returns from the relevant time period wouldn’t be readily available but not having contacted the IRS directly to verify I’m not stating it authoritatively.