Yep, but still.... the files can be different in filesize, yet the installed program itself will be the same. More info and an example of that here:
CookieRevised's reply to MSN Messenger d/l link...
Especially note
quote:
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on both sites it could happen that you come across:
blahblahDL.exe => Installer without InstMsi.exe
InstMsi.exe is the Windows Installer needed to install those MSI packages. It automatically checks/updates/whatever the Windows Installer.
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It might well be possible that one of those two official files was one without the Windows Installer. Usuallly, the file you can download from Microsoft's Download Center is the biggest and "most complete" as it contains all the needed files to install a product. Whereas the files you download from main sites of the programs are often preselected to be installed on certain systems with certain updates only (and thus are in general smaller).