Our Polish PF Migs had the cockpit interior , wheel bays of the grey colour like the cockpit side panels of the PE set. However , the longer these PF Fishbeds were used the more coats could appear. Especially at the wheel bays. these could be either of the silver, grey, olive green or the grass green ( deep "armour green" ) used for the wheel rims. Therefore you would need a pic of the particular plane if you would like to assemble a Polish Fishbed. Generally , using the grey colour is correct for most of early new Mig-21PF used by other countries as well.