I was hoping someone would answer this. The group really needs a Polish version of Cuprum! I'm going to have a crack at answering it, but I'm only too happy to be shown wrong.
My answer is very few wore the full 1919 uniform.
1) While we can't see the colours in photos, the men tend not to be wearing M1919 caps, and I would predict that caps would come first.
2) Many, perhaps even most, re-enactors of the period are in non-M1919 uniforms, despite it being easier if you work from official standards, and they tend choose those elite units you would expect to be privileged. Those guys take their research seriously.
3) The Poles were unable to put many of their new volunteer units in 1920 into any uniform, let alone an official one.
The senior officers wore it, but I would guess most had them separately tailored. Some cavalry, probably privately acquired. Maybe some of Pilsudski’s favoured Legion units. Just perhaps some reserve and volunteer companies and battalions, if the locality had to make a uniform for them.
I have my doubts that much of the Blue Army or the Wielkopolska Army (Poznanians and Pomeranians) wore it. They joined the Polish army late, had surpluses in their own styles, and were proud of their origins.