There are two on each side(one is behind the motor mounts, hard to see) And two behind the fly wheel (bellhousing, and flywheel needs to be off to see them)
6 total.
One other thing, Freeze plugs or what every you call them don't just fall out. The get pushed out because of freezing. Chances are you have a cracked block, not just a "Freeze Plug" bouncing around in your bilge. So check carefully for water in your oil when you run it.
Ahh it was found after a much further review. An excellent bilge cleaning ( AKA had to run it to find it) It did not pop was removed by marina last fall for winterize it.. In 20+ years of boating we had never done that. So just had not experienced that replacement process before. Thank you all.