Hi and welcome back to YOUR thread!My apologies for hijacking it (borrowing it sounds better...lol). Yes, I'm sure it isn't the sensor. I really wish it was the sensor because it's sooo much easier and cheaper to replace that than anything else that could be leaking oil.
I would say those would be fine to use, a little rusty or not. A few of my tools look like that, too, because I have 3 sons who like to "borrow and not wipe off and return tools" to where they got them from. LOL