Hi Henk ,
That's something to consider ; but also when you look at the ricikan (correct term?) of both kerises they are similar even though one is Javanese or Maduran and the other seems Sumatran (cross pollination?).
About the lack of pamor on the Jawa piece; it is a very old blade and if I recall correctly from a past discussion of this one possibly from the Sultan Agung period; also again if I recall correctly there was some mention of a prohibition during that time of pamored gonjos or of openly displaying the pamor of one's keris .
Could this be a feature of dapur; or does dapur not cover the area of the gonjo ?