Very possible. I think that the Ayutthaya-period darb that I have has a peened tang. I tested this by connecting a flashlight bulb, battery and some wire, making an open circuit. I held one wire against the blade, and the other on the very tip of the pommel, and the bulb lit up. So, something was completing a circuit between the blade and the pommel (the fittings on this one are iron, by the way. The handle has a middle section of iron separated fromthe ferrule and pommel by laquered cord wrappings, and I could not complete a circuit here. The alternative explanation is that the handle is made of, or has a sleeve of, conductive material, which is in contact with the blade and the pommel but not the middle section (maybe that is a band slipped around the wrapping of the handle or something).
On the other hand, I have one very beat up dha that is of the style of the second one from the left, on which the flattened pommel had come loose. The pin in the center was essentially a nail holding it into a wooden handle, so what looks like a peened tang may actually be the way the pommel is attached to the handle. Only taking one apart will tell for sure, but that is hard with these things -- they are either loose, or super-solid.