Possibility
Someone swapped a 2006 valve cover in for your 2005. The easiest way to tell is to look at the end of the valve cover opposite the oil filler cap (the short side).

If the end is smooth all the way across, it is a 2005.
If the end has 2 distinct top sections for the cam sprockets, it is a 2006 cover.

 

Sorry for the delay... Busy with other things.

There's definitely two bump outs for the cams. Sorry didnt get a photo but it's NOT smooth.

 

so it is a 2006 valve cover on -----what?

At least that confirms why the oil filler extension tube and shroud are there.

Possibilities
2006 valve cover / 2006 Head/2006 block = 2006 engine swap in
2006 valve cover / 2006 head/2005 block = replacement head w matching cover
2006 valve cover / 2005 head/2005 block = replacement valve cover only

I suppose the best way to TRY to sort this out is
1)to look for the date stamp on the block
2)to look for a date stamp on the head
3)to look for date stamp on the tranny

I'd start w the block since if it is 2006 it's likely a swap in.

Write down the numbers/Letters stamped into the oil filter housing.
Post here and we'll try to sort it out

Only going through all of this so you know exactly what you have should you need to order parts.

As for the oil filler tube extension issue, I'd order a new one with the o-ring.