According to the invaluable ACS Subject Definitions document (available here:
www.census.gov/.../code-lists.html), "some college, no degree" includes two categories: "Some college credit, but less than 1 year of college credit" and "1 or more years of college credit, no degree." So I think it doesn't take into account whether or not the non-graduate has other credentials. Note that there's a separate indicator for thsoe with Associate's degrees.