No the collection returned from a CMR field is live (i.e., you can add and remove objects from the relationship using the collection directly). The collection returned from a query is (or should be) unmodifiable.
A select method is more like a finder than a cmr-field get().
The container creates the Collection but does not "manage" it as it does not correspond to a relationship; this is just like the result returned by a finder.
The type returned is determined by the field or OBJECT cast in the select_clause of the EJB-QL query.