Depressing. Especially when one considers that seals without provenance could possibly be forged, as Sass notes, in the last sentence of the book:
The possibility that our mostly unprovenanced material contains forgeries should always be borne in mind, for the impact of such items on works like the present one is inestimable. (p. 552)In fact the question of authenticity haunts this entire volume. Not only at the end of the work, but at the beginning Sass says "We are dealing mostly with material of unknown origin, and the possible presence of forgeries ... should constantly be borne in mind" (p. 15). In introducing the section on "Names," Sass says "That the body of the material is largely unprovenanced is a considerable disadvantage" (p. 465). In seal after seal, the notation "Authentic?" recurs.
It is interesting that the "Baruch" bulla (no. 417 in the corpus), named in the indictment of Golan et al. as a forgery, is not questioned. There is, however, a notice that the script of the Baruch bulla is the same as that of two other bullae (no. 413, with the name "Gaalyahu," and 535, with the name "Yeshayahu son of Hamul"). These bullae may also fall under suspicion.
I don't know the solution to the problem of unprovenanced or forged material. But as a philologist I know that I would use the names and words contained in the unprovenanced seals either sparingly or not at all; and if I did use them, I would treat them like Barry Bonds' hitting records: to be clearly marked with a big asterisk.
BIBLIOGRAPHY: Corpus of West Semitic Stamp Seals, by Nahman Avigad, revised and completed by Benjamin Sass, Jerusalem 1997. (UPDATE: See also Hershel Shanks, "Fingerprint of Jeremiah's Scribe," Biblical Archaeology Review 22.2 [March-April 1996], for Bulla B referenced below.)
UPDATE: As the comment below points out, the actual indictment apparently considers the fingerprint-bearing Baruch bulla to be a forgery, not necessarily the one on display in the Israel Museum. But surely if one is a forgery, the other is one as well? They were clearly imprinted with the same seal. I can't imagine that Bulla B, the fingerprint bulla, is a fake and not Bulla A. Or do some imagine that Bulla B was faked as an imitation of Bulla A, with the fingerprint added as a special feature? I would think that using a real bulla as the template for a fake bulla would be extraordinarily risky, since the seal impression would have to be, not just similar, but an exact match.
Here's another question: Bulla B famously has the "scribe's fingerprint" impressed into the clay. If it is a forgery, whose fingerprint is it? Could they use this fingerprint to identify the forger?
Here is Avigad's original drawing of Bulla A:
UPDATE II: The fingerprint question had already been raised by Stephen Carlson@Hypotyposeis here.