Installing a Riser?

I finally found a 7" riser on Ebay that the seller didn't think was made of gold and bought it. Doesn't appear to come with spider or bolts. Should I get a spider and short bolts or buy longer bolts? Can you tell me what length bolts for either case?
My guess, if going with an additional spider would be the same length bolts as what's in it now, right? Just want to be prepared when I break the column apart.

Thanks,
Chris