Are these good lead screws?

I just bought this lot on ebay...I'm hoping that I got a good deal.
Any opinions as to why these may or may not be good leads screws to
use to build my 24X x 24Y CNC Router?

http://cgi.ebay.com/ws/eBayISAPI.dll?
ViewItem&item=2585070802&ssPageName=ADME:B:EOAB:US:6

I'm still looking for new/used X&Y linear slides (ball park of 24"
travel) if anyone has a lead on any.

Thanks,

Wade