Get onto sampublications on the net. you want a backorder of the September 2001 issue of Scale Aviation Modeller International. it had a feature on Mustangs over Korea & has colour drawings of a SAAF Mustang No 335 of 2 sqn.
The aircraft number is the last three digits of it's American registration number, carried on the fuselage & the bottom of the leg fairing.
For decals try Hannants in the UK.
Pete