It does look like it was submerged in water for a while.
Did you pull the drain plug to see what comes out of the crankcase?
If it turns over, I'd drain and refill the crankcase with as much diesel fuel as you can get into the engine (all the way up to the cap!), diesel will serve as a good cleaner/rinse and does have a little bit of lubrication to it. Add goodly dose of automatic transmission fluid into the sparkplug holes. For the intakes, I'd just spray some rust dissolver into the intake ports and soak the valve stems, follow that with some spray lube. Then just turn the over-filled engine over (no spark plugs) with the starter to circulate the diesel fuel around and start to lube/clean things up inside. But before turning this engine over much more than a quick test put some new timing belts on it!
After a good amount of swirling, drain the diesel and replace with 4 qts of ATF and fresh oil filter. This is decent lube and also a very good cleaner.
I wouldn't expect to see any kind of good compression readings until after this engine has run for a while. Might not be any compression at all on some cylinders until the crud is knocked off the valve seats and the valves move freely.
The carbs should clean up, at minimum good enough to get the engine to try to start and run badly. Might need to find another set of carbs to get it to run right, but let's just see if we can get it to fire and run at all, first. Squirting an eye-dropper worth of fuel in each sparkplug hole before screwing the plugs back in might help fire this thing up!
Once it's running badly, but running, I'd run it with the ATF in the crankcase, see if you can get an hour's time running it on the stand. After that drain the ATF, replace with cheap oil and a fresh filter.
All this might sound optimistic, but then, after all, it IS a Goldwing, and stranger things HAVE happened.... 😁