Make sure you shop around. There are a number of distributors. I usually check with at least three. Here's a thread from a little while ago that should be helpful:
https://pinside.com/pinball/forum/topic/best-stern-distributors-and-buying-advice-for-nib-pin
If you don't see the distributor's contact info in the thread, just do a quick google search or look for it on Stern's website.
Good luck!