Sorry for the confusion everyone, and I think I need to further elaborate.
About the fighting keris statement, I said it was USUALLY, but not always. Even then, I think the keris is worthy enough for fighting. In Malay martial minds, keris is not to be clashed with or used to parry another weapon, even another keris. So, the fact that it only has 5 mm in thickness does not really matter.
The keris definitely has more than one metal composition, but the pamor metal is not contrasting type or in keris term pamor sanak. Sometimes only one type of metal used to forge a beko type keris.
Maybe the dapor jalak description is not the right choice of terminology for a Malay / Thai keris. If you look more closely, the middle section of the blade is a little wider compared to significant tapering from the base to the tip of say, a Bugis Sepukal, but not as wide to qualify as dapor jalak. Quite hard to explain, and I am sometimes confused myself
And Michel, Nik Rashidin is in a league of his own. I am just a simple collector of Malay / Indonesian weapons who started the hobby just couples of years ago.....