Dear Pak Ganja,
Comparing "keris sajen" (non-weapon) from Indonesia with kind of real kerises (weapon) from outside Indonesia? Am I wrong, if I am thinking: it is like comparing toy-guns with real guns? Comparing small kerises which usually for ceremony purpose and not for weapon, with real weapon.
I believe you misunderstood the purpose of the drawing: keris sajen were not added to belittle Indonesian keris and glorify Malayan keris (nor keris Jawa vs. Malay/Bugis keris since the distribution of these types don't follow current political boundaries...). The aim of the paper was to show the diversity of Malay keris and keris sajen are also found in Malaysia (no idea wether genuine examples were locally forged or if they arrived through trade or migration). Thus, the author needed to include keris sajen, too.
BTW, I don't think that we should place too much emphasis on this collection of rather old papers - just keep the dates when each got originally published in mind and move on...