CANOEDOGS;
Old style salt pork was fresh pork bellies (the same cut as bacon) packed fresh in dry salt and turned every few weeks until cured.
It was harder, and it was dry.
The meat part resembled that dried italian ham (prosciutto crudo?) a lot in texture, though the fat part was still fat.
The salt pork had to be soaked for at least a day to get rid of enough salt to become edible, the same as with salt cod (Bacalao)
It keeps like salt cod does too, forever (over a year?) so long as it is dry

The last time I saw actual salt pork in a store was in 1992. Salt pork, because of the time needed to rinse the salt out of it, is just to hard for most people to use.
All I have seen called salt pork since 1992 is wet brined pork, and it is not the same thing at all.