Oh yeah, and lest I forget to say this....
When looking at previously owned Calfee tandems, it's a very good idea to ascertain some details regarding the original owners, i.e., were they really strong or heavy riders? An even better idea it to get the serial number and contact Calfee to verify that the frame is suitable for your team's weight and to learn anything else about the frame's history that might have a bearing on your planned purchase.
For example, our Calfee was designed to accommodate us, a 280lb team. If we had been a bit heavier, our tandem would have needed a larger diameter top tube to provide the necessary stiffness. So, if we were to sell it, the frame would not be a good fit for a team that weighed, say, 350lbs. Now, not even all Calfee buyers realize this so by all means, ask the seller or Calfee for that additional information. Again, if you call Calfee they'll also have the history for that frame which could reveal that it was damaged and repaired (no big deal since Calfee is one of the few firms that knows how to repair composite frames) or modified in some way that may be of interest to a buyer.