I had a PR-8210 for years (it was my first foray into the LD world).
As I recall, "Search", "Chapter", and "Frame" are on the remote only, and
not on the player. These are pretty important buttons, of course, without
which no random access is possible.
Annoyingly, there is no "CX" button on the remote. So if you do get a
remote for the player, you'll still have to toggle CX on each time you want
it (or decide you don't want it after all).
This unit is really not bad considering its vintage, although if Pioneer
wants you to pay anything subtantial for the remote, I would upgrade to a
modern unit (for improved resolution and tracking, digital audio, et. al.)
instead.