We use gentle redirection to steer them away from this sort of thing. Since we have a visualization system and a POS, we say "Here, let us print out a picture of the mockup for you... or would you rather have us email it to you?". As for their taking down part numbers, we quickly whisk the samples away to the POS and work up the quote. We then say "It's okay, we've got all the information here in the system. When you're ready we can pull up the quote and turn it into an order". This makes it rather awkward for them to say "but, but, we want the part numbers!"