yes, claying should be ok on a freshly painted surface. it's really more of a cleaner/abrasive product so it doesn't have any of the waxes or silicone-based compounds that harm the curing of paint.
just be careful. i have heard that some freshly painted surfaces stay "soft" for a long period of time so you might not want to use a really aggressive clay (the retail stuff like Mothers or Megs should be fine), or clay the same spot for a long time.