According to the articel in the "Lotnictwo z szachownicą" magazine no.51, the Medard Konieczny's Yak-1B ( White 48 ) serial 48184 wore the inscription for 5 months only. Then it was overpainted and the same inscription got the Yak-1B ( White 13 ) serial 13163. There aren't too many pictures showing both of the Yaks.
There are two images of the White 48 published in the article. In both of them we can see the Yak without the inscription. A shot showing the starboard of the kite reveals the Polish checkerboard there. It is not too good seen but it was there. I think it is an effect of being dirty because of exhaust fumes.
The small pic ,you posted above as the last one, shows Cpt. Oleg Matwiejew and Lt. Witold Gabis standing next to the White 13. Later , the inscription there got the Polish translation written below that with a little bit lighter white paint. So , the second to last image shows just the Wite 13 with the kind writting. Also there have been published two profiles of these Yaks in the magazine. There is the Polish checkerboard applied on both of the Yaks. The White 48 is without the inscription and the White 13 with the Russian and Polish one.
BTW ... the White 13 had the front part of the spinner painted white according to her profile.