The tail stars on the photos Lyric1 found of this aircraft do show relatively large borders for their size so I am confident the skin is correct in this regard. One thing I wasn't sure about was whether the aircraft had stars on the upper wings or not. Russian-built aircraft rarely had stars here but lend lease aircraft sometimes did.
With painted-over RAF or USAAF markings I've always gone with whatever VVS shade most closely matches the underlying colour and the tone of grey on the B&W photo, in this case AMT-4 green on top and AMT-7 blue underneath. The photo showed a lighter border around the USAAF markings and I assume this relates to them having the 1943 style red borders.