Hamer Serial Numbers GUITARS AND BASSES OF HAMER U.S.A. 1975 -1996 The guitars and basses described in these pages are those which have been produced by Hamer U.S.A. Over the past twenty-two years. Obviously Hamer also makes many one-of-a-kind custom instruments and the hardware and style of 'production' instruments may be different on Special Order instruments. It also does not include specially ordered very limited production instruments that were not generally available. Therefore the list is not exhaustive. The dates are also approximate and several models do not appear in catalogues.