All SKUs for Windows Server 2008 R2 are 64-bit.
Applies To: Windows 7
Windows Server® 2008 R2 ships with a 64-bit SKU only; no 32-bit SKU is available for the server version of the operating system. However, a 32-bit SKU continues to be available for Windows® 7.
Additional references
For more information, see 64-Bit Only in the MSDN Library (https://go.microsoft.com/fwlink/?LinkID=165635).