In her discussion of the Ka Nefer Nefer case, K.M.Johnston ('Now You See It, Now You Don’t: A Hieratic Scrawl on the Ka Nefer Nefer Mask', Posted on August 7, 2012) discusses further "something that I’ve seen mentioned once in the literature, though I can’t remember where". I do not know whether she saw it discussed here, she's been a visitor to this site before, but here is a discussion of the significance of the damage to the object: PACHI Saturday, 26 March 2011: 'A Question for St Louis'; and this problem will not go away: PACHI Thursday, 12 April 2012 Scabby Hands at St Louis. That damage is very noticeable, yet there is nothing that suggests that SLAM questioned the seller about it either before the sale, nor after when they had the object, and most tellingly of all when they realised (only in 1999) that they'd bought an object from 1951-2 excavations in Sakkara published a few years later and shown in the publication with the inscription still intact.
That photo is quite significant, it was probably taken in 1956 and is credited to the Supreme Council of Antiquities, the significance of that is that the "collecting history" being propagated by SLAM has the object already in Brussels in 1952, so it cannot have been photographed (with the inscription intact) in Egypt in 1956. Unless it WAS in Egypt still in 1956, in the Sakkara storerooms. If there was any correspondence with the seller and previous owner (Zuzi Jelinek) or the SCA (to see if the negatives survive and there is any documentation of where and when those shots were taken), trying to get to the bottom of this discrepancy, it apparently has not survived in the archives of SLAM.