Hubcaps cover the hubs only, these are actually wheel covers.

See the 1970 page at https://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1970/70_Dart0008.jpg & you can see they are not correct for a '70. You can also see the correct type there for W11.

Also see the 1969 page for the type you have at https://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1969/69_Dart0012.jpg

1968 also - https://www.hamtramck-historical.com/images/dealerships/DealershipDataBook/1968/68_Dart0014.jpg