I haven't seen evidence of this anywhere. HX feautures manual specifically lists for XU3 and XX7 as one of the feature changes:

"Kingswood door Trim & Hardware Complete".

The latest HJ example of the same thing I have is dated 30/1/76 and there is no mention of Kingswood door trims. The only difference in that area between the 1976 document and the 10/74 equivalent is the addition of armrests as standard with XX7.

Having said that there was a major trim revamp in 1976 with vehicles appearing around 4/76 and if XU3 and XX7 were to have gained Kingswood door trims this is when it would have occurred. However I would have expected to see evidence this in the ordering procedure I have which is dated 1/3/76 (this procedure contains the Features manual pages). I believe the features manual I have is the last for HJ.

In addition, there is no mention in any HJ parts catalogue I have seen about any XX7/XU3 getting Kingswood door trims, eg 19V is the same part number for all HOLDEN/Belmont. Whereas HX and HZ are all over it, where it lists the Kingswood trim as Kingswood and Sandman.

On another note, is that seat buckle in the brochure picture hanging on a clip? It shouldn't have retractables as it is the HJ release brochure, looks like the buckle is attached to a support clip on the shroud which i show I think I remember them being. Good luck replicating this on an early HJ Sandman!