Older Outboard identification number

[boatyard13]

I just bought older runabout with Mercury 70 outboard. Missing transom bracket serial number. Some say, "it's on freeze plug. No freeze plug to be found. Anyone know where else I can look? Ya'll were very helpful with my other boat, thanks.

 

[haventaclue]

Maybe the starter motor bracket, up near the flywheel.

 

[boatyard13]

I'll look thanks.