In the late 1980's I began corresponding with Prof. Jerzy Piaskowski
https://prabook.com/web/jerzy.piaskowski/19271
Prof. Piaskowski had a particular interest in keris, I supplied him with old, damaged keris and gonjos, as well as societal & cultural background information. We maintained contact & keris discussion until the time of his passing on February 2nd, 2013.
Prof.Piaskowski carried out a number of examinations of very old Javanese & other keris & gonjos, & published papers on the results of his findings.
He identified at least one gonjo that had been made from wootz. He probably had more than this single wootz gonjo in his possession, but results of only one examination were published.
I believe that it can be taken as a given that wootz was used in keris & probably other weapons, and that this wootz was imported. My understanding is that there has been no credible evidence produced of smelting activity in Jawa or Sumatera.