[Jeeper6]

I am guessing the housing part must have a cutout where the gasket sits inside...as does the support housing where it bolts to the block.

...they must usually do just the cooler alone with the actual support housing insitu, as I recall when I had the cooler replaced on my previous Jeep, the comment was made when I turned up with the whole housing to replace, that it would involve more work for the mechanic. They didn't charge me any more than the original quoted price for labour though...