G'day Fabio,
The Centurion III that you show the box art of is the 2 reissue of the Tamiya Kit, the markings in this are for an A or C Sqn 8th King's Royal Irish Hussars, Korea '51, C Sqn 5th Royal Dragoon Guards, Korea '52 and a C Sqn 1st Royal Tank Regiment Korea '53.
The markings of that particular Centurion was from the Original Box released in 1971. As I have these particular decals for this particular Centurion Mk III, as per my photo I converted mine to the Aussie Mk V as used by our Forces in Vietnam.
If you send an email to me at scalemag@telpacific.com.au
To arrange getting these too you, with a copy of the marking sheet.
Rob.