It is a shame that he didn't fix what he didn't do before this date.
I too am very concerned about Novus Ordo Priests functioning in the SSPX without being conditionally ordained.
One other option some might have is that, if you're questioning whether a particular former Novus Ordo priest has been conditionally ordained, is to find some way to contact Bishop Williamson and ask him. Back when he was active in the SSPX I was told he "saw to" the conditional ordination of many of the Novus Ordo priests working with the society. He's obviously been out of the mainstream SSPX for a while now but if the former Novus Ordo Priest in question (such as Fr. Pieroni) has been in the SSPX for a while Bishop Williamson might have information on whether a conditional ordination was done; at least if he was the one to do it.