Mercury does not go by model #s only the serial # matters. The kiekhaefer does not matter either. Your motor is a 1968 6 hp outboard unless the serial # you gave us is wrong.
OK thanks, you're probably correct. May I ask how you found that? Serial number is correct I have searched it numerous times and came up empty. It does sat "Merc 60" on the cover.. would that be a model?
As for the year I was just going off what the PO told me. He said it was his father's but there is a sticker on the top from 1974, I believe that is just some sort of registration at the time. He might have been wrong about the year.
Update: I did in fact search Merc 60 and it came up for 1970-2017 and my serial number is correct for that. So it most likely is a 1974, thanks for the help!