Are they looking at the RuneScape Private server scene? I remember some OSRS servers that provided custom clients from those years. I don't know how accessible some of those are now, but it wouldn't surprise me if you could find those old clients that way.
There is a project by a RSPS community member to accumulate all caches (https://archive.openrs2.org/) by similarly asking people, pulling from other archives, etc. This is probably the best archive in the rsps scene / I'm sure they are aware of it, there are just caches nobody has.
> These didn't focus on keeping a historical archive of all versions of the game; only a handful of old game versions were found from these sources. Everything that was available from private servers has already been saved.
