They are probably to let the SP3 installer know what patches you already have installed, so they won't install those patches twice.
And nice Swans M200s. They are friggin awesome. I have a pair of them, but they are sitting in a closet somewhere, because I don't have the desk space to use them at the moment.
In Windows 2000 any hotfix would show up 'pre-SPx' to denote that the hotfix was released prior to a specific hotfix, likely coincides with what kent1146 mentioned (so you don't have the same ones applied twice).
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