Help needed checking year off a te250 engine

Hi,
Some years ago i bought a oldie te250 (2005 version ) that had a more recent engine (the owner told me he had replaced it on warranty in 2006-2007).
I want to install a 300cc kit on it but from what i have read there are 2 version , for 2004-2005 and 2006-2007 (or later).
My problem is that i really need to know what engine was put on the bike by huskvarna and i dont know how (can call husky/ktm now for help ).
So the big question is how can i check this ? (i have only found info regarding the frame ID).

What is the engine number ?

I can only find this on the engine (didnt check under the bas plate).
Is this a date or something? (06 like 2006)

That looks like the cylinder not the motor block.

The 131206 is on the cylinder, the 23x6 on the block . where should i check for it on the block? cant see any numbers beside those

A engine number for a 2006 TE 250 would be like this: H8A603560.

I think i found it, but hard to read and hidden by the pipe.

8000A5307 425A /1 2

NOPE... this is also the cylinder head, but at least online i can find people talking about having it on 2008 bikes so it must be a 2006-2007 because mine is not FI...