Those teeth look pretty worn to me. They're not particularly hooked but there's a lot less meat there than a new one.
As for the new one, if that part number means it's a 520 size, are you sure your chain is a 520, the standard chain is a 525. The difference is that a 520 is 1/4" thickness sprockets, a 525 is 5/16".
There's not a huge difference in strength but the 520 will probably wear faster, and you definitely shouldn't run a 525 chain on a 520 sprocket.