I'm guessing that CLA-1A (capital 'A') is a Ricky Pushkin designation for concentric circles. "Black's Catalog" list a CLA-1a (lower case 'a'). Difference between CLA-1 and CLA-1a description published in Black's Catalog" is the CLA-1 is a light green imprint. CLA-1a is a dark green imprint.