Yup, those are the ones I ordered, a few of the cheap ones and a couple of the expensive ones. I'll have them next week sometime and the first thing I'm going to look at is the metal they're made out of. That chrome color is a good sign.
I've actually got that same concern myself, sealing that is. I need good sealing on the atty to protect my PCBs from
juice. PG is actually pretty corrosive to soft metals and has similar conductivity to water. It will cause problems for electronics when it comes in contact with the PCB. I've proved that for myself.
I use the solid center posts and if not, I fill them with solder, but I would rather use the solid ones to begin with. The inside part on any of these connectors seems to be well sealed normally (as long as it doesn't have a hole in the center post).
It's the mating surface between the atty and the enclosure on the outside that would be the next concern. For a bolt down job, which I plan to do, a thin layer of silicone sealant applied to mounting hole beforehand should take care of it I think. I have another one that does not use a chassis mounted connector and that's going to be more tricky to seal. I'm thinking in terms of a silicone o-ring on that one.