Cavalier Mustangs
 

Were any Cavalier Mustangs new build or were they all refurbished and modified?

google 'Cavalier Mustang' and Wiki will reveal all.

All rebulit
 

All Cavalier mustangs were re-assembly of various old stock mustangs, no new airframes. They did get new serial numbers.

Good description here. Warbird Information Exchange ? View topic - Cavalier Mustang Construction Numbers

I did, but Wikipedia isn't always the most reliable of sources and some other references are a little ambiguous.

Have a look here for Mustang info;

The P-51 Mustang Variants: P-51D -MustangsMustangs

There was quite a market for refurbished P-51's after the war, another notable player was Temco (later LTV) who invented the 'TF-51' (not an official designation) which involved putting a second seat into basically a stock airframe but with a canopy of larger profile to give more headroom for the second occupant. Our "Miss Velma" at Duxford is this variant.

The "Cavalier 2000" variant added wingtip tanks, borrowed I believe from the Cessna 310 design.

The P-51 Mustang Production Count -MustangsMustangs.com:

I was puzzled by this page which seems to imply Cavalier 'production' of 19 aircraft, (I think a couple are turbine Mustangs) which was why I asked the original question. Does this just refer to cases where it's impossible to relate the various bits to an original identity?

There's one stored in a compound at Edwards AFB along with a bunch of other interesting retired a/c.

It's N482PE. I think a 'new build'?

It's a PA-48E.