Nick: undoubtedly so.
To be honest, I had never noticed but then, I’m not a planetary astronomer.
I foresee a very vigorous, not to say rancorous, debate over whether J2000 is kept in perpetuity or whether we move to J2050 within this decade.
Closely related: proper motion already affects my code which attempts to match Gaia data to historical positions. A surprisingly large number of stars have moved more than 2″ since 1950. One day I really must download the PM data too and do the job properly.