Thanks to all. Bill I have couple of NOS 6550 pumps and the blue imprint on both are only smudges. Yours is the best I have seen so differences on other pumps may or may not be out there. The dates on the boxes are Feb 64 and May 64 but to actually tie that to the manufacture date would not help. Actual date can be determined only with the pump disassembled. A clock date or dots are on the individual parts. I would bet the blue stamp is either a batch or test number. I can`t say for certain why so many I have viewed are not crisp imprints but it tends to point to a tested component and the tester has a very wore out stamp or just in a hurry. Either way it indicated OK Tested.
|