Hey... I recently purchased a sempron64 2800+ cpu. I haven't opened the box yet as I noticed the code on the cpu says BA and not BX. It does have the AMD64 logo on the box however. Did I get a dud 64 bit chip? Are there BA 64bit semprons out there?

You got a Sempron Rev. D0 (Winchester based) that got 64 Bits support enabled. They are officially recognized as Retail versions as SDAxxxxCVBOX (In the Link that you provided, that OPN is written, so it is). Read here' ">http://forums.amd.com/index.php?showtopic=56575.