You will find those same cross-bolts on both sides of the motor. On the Port side (passenger side in a car) if you ALSO have small pipe plugs about an inch above those cross bolts (Port side ONLY) then you have a side oiler.
The side oiler version of the 427 did, indeed, show up in marine motors from time to time. I think it was caused by Ford having to supply motors and they decided to ship side oilers because they had a stock of them. Normally they are not found in CC boats or Roamers, but I have some friends who have them, and they are proof that the side oilers did, indeed, show up in (some) boats.
The side oiler is not going to produce any more power or last longer, it was only intended for the track, and it has a more expensive milling operation to gun bore the Port side of the motor to allow oil to get directly to the main bearings. My 427 motors (and yours probably) are the standard 427 with center oiling system.
If you have a side oiler, you have the bragging rights, and the rights to a more expensive rebuild due to different cam bearings being needed. Otherwise, neither you, the motor, or the boat will really tell the difference. In NASCAR racing the side oiler would allow a blown cam bearing to remain in service without starving the mains, and this would allow the motor to run a bit longer and perhaps finish the race.
Glad you enjoyed the links, I've put a lot into them, and I'm pleased to be able to share this stuff with the Ford guys on my allied Network54 site. Here's a photo of one of my center oiler 427 motors.
Awesome chunk of American iron! I'm running a pair in a 1966 38' Commander, by the way.
REgards,
Paul