Don't be too drawn in by the "1 of 214 example of a Maserati 4200GT where only 214 cars were built in right hand drive manual format!" the numbers are wrong, it's rare, but not quite that rare.
I think that's based on the howmanyleft website numbers perhaps, but the problem is, they don't always seem to have been identified correctly when registered.
Mine for example is a Coupe GT on the reg doc, but when I do insurance quotes / the 1 time I called for recovery, the database both insurance and recovery firms used list my car as a spyder!
Numbers wise, even Maserati don't get it right, if you look here:
1 person contacted Maserati and was told
"The majority of RHD GT Coupes made were imported into the UK (877 of the 1078 manufactured)."
Someone else was told:
"Maserati produced 1078 4200 manual GT Coupes (3 pedal kind) M138 for world wide markets. 214 cars were produced for UK RHD market. They also went on to confirm that 89 Coupe GT's /Spyders were face-lift models but didn't specify the breakdown of CC's/3pedal within the 89 face-lift cars."
But we now have either 1078 Coupe GTs total, or 1078 RHD total - I think it's 1078 RHD Coupe GTs.
Anecdotal perhaps, but in my ownership, too many other cars have been seen / for sale for the total to be close to 200.
I remember shortly after I bought mine turning up at an Italian car show (not a massive show, and I'm up in Scotland) and there was something like 8 4200s there. 1 was a GranSport, 1 a CC and 6 manuals. My manual was sitting at home and I'd viewed another (8th) car a couple of weeks before.
Good luck with your hunt