The old one, on the left.
Thanks @sportmaster . I've since learned that the newer-looking one on the right is the "V4" driver that HP introduced a few years ago, not exactly sure when. It's not a specific Z3200 driver, it's an omnibus driver that includes a lot(!) of HP printer models. (Unlike my old Z3100 driver which is for that model only.)
I've also learned that the driver version number shows the year -- "61.yy..." where yy is the year.
What version is yours and where did you download it? Is it the PCL3 driver, or the Postscript driver? I have the PCL3 driver 61.2313.0.100, released Jan 2024(!). I can't find any older PCL3 versions. I have a Rev B printer if it matters (Q6720B).