The 1937,35,32 and 30 catalogs only list four grades. I have several high grade guns from the 1930's and a 1930's grade four has "gold inlay with green and yellow gold against a deep black finish".

I have several other A5s from that period with sales papers. # 798xx = 1930, # 1008xx = 1931, # 1660xx = 1935.