I realy don't want to cramp somebodys style here but these bird are some mix between Yak-9U and Yak-3. U/C doors are same as on Yak-3 rest is Yak-9. Are these rebuilt Jak-11 trainers?
For line drawings of Yak-9 (early models) including U/C look here:
Modelist - Konstruktor magazine (in Russian) No.5 1976:
http://mkmagazin.almanacwhf.ru/avia/yak_9_mk7605.htm
Built model of Yak-9's in 1/72:
http://vvs.hobbyvista.com/ModelGallery/yak9_72.php
and 1/48:
http://vvs.hobbyvista.com/ModelGallery/yak9_48.php
Yak fighters (Yak-1/3/7/9) fuel gauges filler caps (article):
http://vvs.hobbyvista.com/ModelArticles/Yak_Fuel/index.php
For line drawings of Yak-9 (early models) including U/C look here:
Modelist - Konstruktor magazine (in Russian) No.5 1976:
http://mkmagazin.almanacwhf.ru/avia/yak_9_mk7605.htm
Built model of Yak-9's in 1/72:
http://vvs.hobbyvista.com/ModelGallery/yak9_72.php
and 1/48:
http://vvs.hobbyvista.com/ModelGallery/yak9_48.php
Yak fighters (Yak-1/3/7/9) fuel gauges filler caps (article):
http://vvs.hobbyvista.com/ModelArticles/Yak_Fuel/index.php