Richard Peterson's P-51D.........

without the finfillet (right word and speling?[:I]) where can I find it in 1/48?
Also, why did he get the nickname “Sheppard of the sky”?

The Hasegawa 1/48 kit has the area to be removed engraved on the inside of the fuselage halfs which makes it an easier task. For the Tamiya kit, there is a resin replacement from Cutting Edge that only requires minor surgical skill. As far as I can recall, there is no kit without the fillet.

Regards, Rick