Gus Viseur spent most of his professional career playing musette with his two flute reeds dry tuned in unison. I almost bought a Cavagnolo box tuned the same way. It only had two treble reed banks with the coupler giving the facility to switch one or two reeds on. It was a beautiful looking instrument, but I decided against it as the Cavagnolo build quality at the time was questionable.
Gus Viseur also played a Cavagnolo which had a beautiful bassoon register without cassotto, which I believe has been reproduced on Cavagnolo's current "Manouche" model.
Emile Carrara played single reed amplified accordion for a time which sounded awful, but he got away with it. Louis Corchia and Bruno Lorenzoni did the same, but they managed to get a better sound. Andre Astier, Joss Baselli, Joe Rossi, Raymond Siozade, Jacky Noguez, Claude Nouyes, Louis Legrand, Louis Camblor, Marcel Azzola, Jo Privat, Tony Fallone, Tony Murena, and many others hardly ever recorded tunes on full musette at all.
Problem always has been that we foreigners all tend to associate French accordion with those romantic Parisian airs played on sentimental sounding full musette accordions. For a long time after I became interested in French musette I wouldn't even listen to players who never played "musette pur", and it was only after I learned to play a bit that I realised that some tunes weren't written to be played with three voice musette.
There is no doubt, however, that French spec accordions do tend to have have that French sound about them that is not present in other accordions, even on single reed registers. I'm told this is because the reeds are pinned on leather, but do not have enough technical knowledge to confirm that. I have a Marinucci LMM Italian made accordion that I occasionally use to play French musette tunes on. It is a very nice instrument, but somehow doesn't quite manage to get that French ambiance over.
Here in Scotland French musette tunes are regularly played with Scottish musette tuned instruments, and although it sounds strange to me, a good player can make a passable job of it.
Richard Galliano often plays his version of musette using two straight sounding voices on an Italian built Victoria accordion, and it sounds just fine. OK, it might not do for some of the older stuff, but musette has diversified into various different styles. That said, it seems that the younger players have revived the three voice full musette accordion, but I've not kept up with the modern scene very well, so I'm not really sure what is going on today.
I reckon Glenn's advice to just play musette with what you have is a sensible approach, and don't worry if your instrument doesn't have full three voice musette. You don't need it.