I believe that gasket goes between the crankcase and barrel.the copper gasket goes between the barrel and head.
You should put the head on just for a mock-up and make sure that the pushrods can get on the rockers correctly, without rubbing the barrel.It is quite common to see some misalignment on these pushrod holes in the barrel. I see it all the time. Yours is more severe than most.
Looks like your barrel is way off can you return it? ERC
Maybe. It's one of those "rigorously inspected" alloy barrels from Hitchcock's. I'm considering just sticking it in a drill press and elongating that hole...