When importing an Illustrator file, should the colours used appear in the colour bar?
That depends of the EPS Translator choices
The file in question looks fine. All the colours are correct, but there are no entries for them in either the colour bar or the colour menu (apart from extra "[Registration]" and "100% Black" entries).
Tested the file with Artworks 2.61 and I do get colournames. It depends if you switch off the option 'Use unnamed colours' in the EPS Translator Choices window. If it it's on then I get the same result you describe.
So put out the use 'Unnamed colours' option and it should work fine.
But I found some other bug with colours when importing Drawfiles. I switchted the option 'Create as editable colours' on 'All' for draw import but when I import a Drawfile with some colours, the first used colour is not on the list unless it's a standard Draw colour.