This is what I find below my ~/.m2:
-rw-r--r-- 1 x x 711693 2011-05-02 14:12 ./org/mvel/mvel2/2.1-SNAPSHOT/mvel2-2.1-20110501.033205-24.jar
-rw-r--r-- 1 x x 711693 2011-05-02 14:12 ./org/mvel/mvel2/2.1-SNAPSHOT/mvel2-2.1-SNAPSHOT.jar
At that time I didn't build anything except droolsjbpm/drools, so both must have been downloaded by the same build.
-W