My research says it is a simple enough conversion as most of it are internal differences…however, the prop is at issue…was it cuffed or uncuffed?
The P-51K (RAF Mustang Mk IVa) was usually fitted with the so called “Dallas Hood” as well as well as the Aeroproducts propeller. In addition P-51D and K models supplied to the RAF (including Canadian squadrons) were fitted with a louvered intake covers. It was found that the Aeroproducts prop had a detrimental effect on perfornance. Some sources say it was 25 mph slower. For this reason the K could not be operated with the D and so it was used almost exclusively in the ground attack role.
You do not say which scale you are interested in. In 1/48 scale the Tamiya F-51D Korean War Mustang kit includes the Dallas Hood but not the Aeroproducts propeller which you can get from Ultracast. Authentic Decals sheet 48-02 American Propeller Markings has the Aeroproducts logo and stencils for the prop. IPMS Canada produced the louvered intake covers and also “Sweating Beaver Decals” which include templates to stick to the Hamilton Standard propeller so that you can reshape it to the correct Aeroproducts profile.
Don’t know about 1/72 scale.