Get App Version 32/64 bit?

using System;
using System.IO;

public enum MachineType {Unknown = 0,
                          x86 = 0x014c,   // IMAGE_FILE_MACHINE_I386   Intel 386
                          i64 = 0x0200,   // IMAGE_FILE_MACHINE_IA64   Intel Itanium processor family (64-bit)
                          x64 = 0x8664 }  // IMAGE_FILE_MACHINE_AMD64  NOT! AMD 64-bit processor ???

//UPDATE : Seems IMAGE_FILE_MACHINE_EM64T = 0x8664, as well
//http://msdn.microsoft.com/en-us/library/windows/desktop/ms680309(v=vs.85).aspx
//Intel, reacting to the market success of AMD, admits it has been developing a clone of the AMD64 extensions named IA-32e (later renamed EM64T, then yet again renamed to Intel 64). Intel ships updated versions of its Xeon and Pentium 4 processor families supporting the new 64-bit instruction set.

public string GetAppCompiledMachineType(string fileName)
{
            const int PE_POINTER_OFFSET = 60;
            const int MACHINE_OFFSET = 4;
            byte[] data = new byte[4096];

            using (Stream s = new FileStream(fileName, FileMode.Open, FileAccess.Read)) {
                s.Read(data, 0, 4096);
            }

            // dos header is 64 bytes, last element, long (4 bytes) is the address of the PE header
            int PE_HEADER_ADDR = BitConverter.ToInt32(data, PE_POINTER_OFFSET);
            int machineUint = BitConverter.ToUInt16(data, PE_HEADER_ADDR + MACHINE_OFFSET);
            return ((MachineType)machineUint).ToString();
}