Totally right of course. Yes sometimes its just a matter of front end gril or decals set to change the things. Those are available or can be reproduced. An example? The Grp2 2600 RS Capri Ripolin driven by Yves Scemama belongs to the front running batch in HTC series by PA. Originally was a 1300 XL.
To go further in your quest-ion, you dont have to choose between two appendixes, K or J, you must comply with both so K and J. Plus your homologation form, plus proof of what was legally used in period. It sounds as a hassle but is not.
Apart from this I find the choice of a DAF a good and original one. Just my opinion.