I can tell you what mine has. I have a 1983 37CC.
I do have the Perkins 4-108.
I have a rubber hose that comes off the exhaust manifold on the port side of the engine and goes to the water lift muffler. The water lift is also on the port side, behind the engine. I don't have any hoses that cross the engine, or any anti-siphon loops in the exhaust.
From the water lift muffler it goes to the exhaust outlet on the port side of the boat, directly to port of the engine. Right where you described yours.
The 2 inch thru hull you describe under the hallway is where my engine raw water intake is located.
In thinking about it, I think the exhaust from the water lift goes up the back of the engine compartment, across the top of the engine compartment, down about halfway forward in the engine compartment, then across and to the exhaust port. So, I guess this acts as anti-siphoning.
Doesn't make too much sense on yours why they put the water lift on the opposite side of the engine compartment from the exhaust manifold.
Don't know if having the exhaust under water would work. How could you verify that water was coming out? And, seems like this really would cause back pressure.
And, why would you want to miss the pleasure of having the exhaust sometimes coming back over into the cockpit? :-)