Welcome to the site Dave.
Just the usual things to look for. (as mentioned by others already), as Falcos are very reliable if looked after and don't corrode as bad as most if used in winter, (I've run mine through six winters).
The Falco's big V Twin is not an easy thing to turn over, but mine has always started first time if the batttery is up to it. Take great care and if the battery is low charged, it as it can damage the Sprag clutch and cause dash resets with EFI displayed. Best to keep it on an optimiser of some sort then even an older battery should be OK for a while. If it does need a new one see the threads on here about batteries with a higher turn over capacity, which can be worthwhile)
As for cans, yes get some, but never heard of Pipewerx, I use Beowulf cans, as do a few others on here. They are fine with the standard chip if you leave the baffles in. They are bloody loud with them still in!
I fitted a K&N filter at the same time and they worked perfectly together.
Others have fitted Blue Flame and Fuel and they seem to work well.
I would fit a hugger early on to keep any crap off the shock.
Good luck with your search or purchase if you go for the one you've seen.
Only problem is they always say never buy the first bike you see, but you don't see many Falcos!