Or maybe the blades were replaced with the mono steel variety. Sort of like selling the baka-baka, or other silver/ gold fittings, but in reverse, sell the nice laminated blades, replace it with mono steel and hide it in the scabbards.
I dont' believe that a datu would intentionally comission a non-laminated blade, I think that the blade would be just as important as the hilt. The datu would have to show the blade off, just as we do now as collectors.
Scenario:
Datu Itom along with his posse bearing his ivory and silver hilted(insert weapon here), goes to visit Datu Puti's kotta. After all the nods, handshakes and baby kissing, they both retire to Datu Puti's crib. Datu Itom then unsheaths his (your choice), and shows off the nice twist core pattern, highly laminated blade. What does Datu Puti say..
. If it sported a non-laminated blade....
I've had 3 whale bone kamps pass thru and all of them had laminated blades. I have also seen ~5 with laminated blades. Same with my barung blades with chinese characters- they all have laminated blades.
My theory is they have been replaced or maybe of post 1930's manufacture.