Got the same stuff, very nice to have around, works great for specialty things like this. It's a nasty goo but it is the real deal and very easy to take apart down the road. Turns to sap like consistency over time but non hardening. Here's what it looks like in the wild, one this size goes a lonnng way.
If you want a really gluey sealant I also trust Three Bond 1184 (aka "Honda Bond") to stay in place. Good for problematic seals on moto crankcase covers and such. It seems pretty similar to the quicksilver bellows adhesive with it's glue-like bonding ability but I've never used it in a bellows before. I went with the quicksilver stuff.
The top picture is exactly what I have as well . I do not know why the description on the Permatex website calls it #3, but it does not say that on the jar??
Merc said to use adhesive, OMC said to use sealer, I'm still in the OMC tribe for now so I use the sealer. I can say this, using that sealer keeps out water well, the gimble housing flange looked brand new when I changed the bellows last time. I have seen some that were so rotted that you'd never get a good seal.
guessing #3 is just the old name, like the #9 at D'Angelo's