Is there a difference in 2004 and 2005 lq9 engines?

[2wd73blazer]

I bought a lq9 and I was told it was out of a 2005 Escalade. It has a fan on the water pump. My 2005 Denali has electric fan setup. That makes me believe it is actually 2004 or older. The reason I ask is while buying parts i discovered there are different part numbers for head gasket kits for 2004 and 2005 and don't want to buy the wrong thing. If anyone knows of any differences I would love to know what they are.