Thank you, Mark V and flyernzl, for those explanations.

I find it a little surprising that, in this security conscious world, the US authorities, above all others, are willing to permit aircraft to fly, in their territory, carrying “disguise” registrations. That is less difficult to comprehend in the case of an ex military aircraft, of a type long since out of military service, being permitted to fly in military colours and carrying a “disguise” military serial. In the case of aircraft carrying a “disguise” civilian registration mark, is that permitted only if the aircraft was, or is of a type which was, constructed a significant time ago? If there is not a “vintage only” rule, it seems that this derogation from the general principle could cause a degree of unease. I wonder what the US authorities would think if, for example, the Somali authorities permitted their aircraft to fly with “disguise” US registration marks. That might be quite an attractive proposition in certain quarters!

The photo of the “set aside” Rapide fuselage is interesting. Hopefully it will find a more appropriate use than fire wood. Maybe a static restoration or replica. And whilst on that subject, if N89D now flies with a new build fuselage, how much of the original aircraft is there now in it? Is that which appears in the photos a restoration or a replication? If the original fuselage is used for something other than firewood, in the future will the question be asked: will the real Rapide c/n 6709 please stand up!