Thats around what they went for new. They dont make em anymore. I got mine used for 345.
Before my hardrock was stolen, I had a Marzocchi Z1 on it. I loved it. I think 130mm is perfect for the hardrock.
I recommend the fox vanilla fork too. It has QR dropouts so you wont need to get a new hub or wheel, and it has lockout for xc, and a low speed compression adjustment.