Ashley, Janean and Liz,
I just wanted to add that I think it would be bad practice to simply append an ‘a’, ‘b’, ‘c’ etc. to the end of the existing number ’71’ number.
Letters should be used to represent component parts of an artifact, not distinct artifacts. The classic example is the teapot and lid. Teapot would be 2013.1.1a and the lid would be 2013.1.1b.
Six coin purses should all have distinct numbers, they are not component parts of an artifact.