I think what you have, then, are D'Addario's 45-100 gauge EXPPBB170 strings. They
are coated, but with some kind of plastic-y stuff. They also seem to be very popular as factory-installed strings. They're also available uncoated, as EXPBB170s. If you like the ones you have now? Great. D'Addario strings are usually pretty easy to get hold of; in fact, sometimes it seems like they're the
only strings you can get - for anything; especially around here...
Several other companies make those strings, if you decide you want to try something else. Most are uncoated, though. And, if you want to try the 80/20 "Bell Bronze" strings, Elixir and Ernie Ball makes them. The Elixirs are Nanowebs - their coated string series. 45-100 gauge seems to be the universal standard for all of them, too.
If you want, you can always Google "phosphor-bronze strings"; you'll probably find out more than you really want to know about them. Same for the 80/20 strings. Anyway... enjoy your bass!