2003 oil cooler issue
 

I bought a 2003 dmax for a project truck recently, it had a broken bellhousing and adapter plate and a bunch of other small quirks. I fixed most of the small stuff and sent the truck over to a buddies shop to do the bellhousing as I'm tied up with other projects. Anyway he called me today and told me its got a coolant leak from a crack in the oil cooler elbow (which I had him order from GM) the problem is apparently you cant change the elbow with the adapter plate installed unless you remove the oil cooler. He talked to GM and they told him they no longer sell gaskets for that oil cooler because they upgraded the part and that I need to buy the new oil cooler and gasket set.

So I have two questions here:
1) Can I source a gasket set for the original (2003) oil cooler setup?
2) Can I install that gasket set and new elbow without taking the adapter plate back off?

Thanks guys!