Just to answer your questions, yes there are keys defined and these are regular tables, not views.
Having said that, as of today I am now able to see and work with the geometry in Map 2013. It looks as though it might have been a DB permissions issue afterall. I thought that the user credentials I was logging in with were set up as data owner, but I had our IT dept. help out with some related data access problems, and in the end this user id was set up in SQL Server as sysadmin. I didn't have a chance to test this on Friday when he made the change, but it is certainly working today, so I have little doubt that this was the fix.
I appreciate your time spent with me on this, and I feel a bit sheepish about not paying more attention to the db roles thread you linked me to in your earlier post. Anyway, yay, it's working!