Using cleartool I am able to find all the files associated with a label using something like:
ct find -avobs -version \"lbtype (Build-Label)\" -print
There is a another way to do it , where LABEL1 is the old label and LABEL2 is the latest. Check the date of creation of the labels and swap them before issuing the command as it prints the negation of the && conditional statement. Works like magic!
$(cleartool find $PWD -ver "!lbtype($LABEL1) && lbtype($LABEL2)" -print)