Fake Intel CPUs

I recently purchased a processor off eBay that was labelled as an Intel Core i5-2520M. It came shipped in just a tray, not the original box, but the processor and all its markings look perfectly legitimate.

My system BIOS reports it as a Genuine Intel(R) CPU 0 @ 2.50GHz and shows the CPU-ID as 206A5, which, when I stick it into Google, turns up the Intel Core i7-2720qm instead.

The CPU seems to work fine for the most part and runs Windows 8 64-bit without issues, although it is giving me some trouble with AMT, but I'm not sure whether this is a CPU or a motherboard issue.

So, this leaves me with a couple of questions:

• Is it possible to update the microcode of a CPU to pass it off as a different one?
• Is it normal that a genuine CPU gets reported as "CPU 0" in the BIOS rather than its actual ID?
• Could this chip be an engineering sample?
• Is there a software tool that will check whether a processor is genuine?

I ran CPU-Z and it reports the following:

Name           Intel Core i5 2450M (hmmm...)
Code Name      Sandy Bridge
Max TDP        35 W
Package        Socket 988B rPGA
Technology     32 nm
Core Voltage   0.792 V
Specification  Genuine Intel(R) CPU 0 @ 2.5 GHz (ES)
Family         6
Ext. Family    6
Model          A
Ext. Model     2A
Stepping       5
Revision       D0
Instructions   MMX,SSE,SSE2,SSE3,SSSE3,SSE4.1,SSE4.2,EM64T,VT-x,AES,AVX

Should it look like this for a 2520M CPU?