Hi Audrius,
thank you for sharing the photo.
The wire aerial corresponds to that of Yak-3vk-107; the panel overposed to the star isn't shown on the drawing on Loctnicze, but I cant assure its reliability.
Note the wire aerial from the tail horizontal surface to the fuselage side, aside the upper aerial.
I think to see a pair of panel lines on the stabilizator and under the tail, but I'm not sure.
I have photos of Yak-9 U and UT without the radio mast, so Yak-9 is more likely for me.
Pity! None photo of production Yak-3U is known to me. Only prototypes.
BR Massimo