I certainly agree with you on specificity Alan. However, what i think we are trying to establish in this case is the likelihood of a well dressed keris with old kinatah or other gold embellishments being a "Royal Keris". To get an idea of that likelihood i would say that any tales of specific proscriptions would at least get us started in this discussion. Of course, to get specific here, that first keris posted in the original question appears to be a Palembang keris from (perhaps) some time in the 19th century. So if we are going to answer José's question we need to be looking at the Palembang court from that time period. I have not personally found much reading material on Sumatran courts and don't know if finding the answer here is possible or not. As with many things to due with the keris, answers are not always available. That does not usually dissuade me, however, from asking the question.
I also have a nice Palembang keris with a very similar gold pattern applied by what appears to be the same method. I agree with you that this (and mine) was most likely owned by a wealthy man such as a merchant rather than a a royal. So to couch my question more specifically, are you (or anyone) aware of any particular proscriptions on having gold on your keris in the Palembang court from this time period? You are, of course, correct that we would need to look closely at the specific court and time period for any keris we were to poise this question about and take them on a singular basis.