That seems to be exactly the meaning of the sidebar saying that anything that has changed here has changed, but that there are other trading post contents in other books.
It says:
THE BLACK MARKET, RARITY AND LEGALITY RATINGS
Older publications may reference the Black Market, treat any of those abilities as referencing the Trading Post instead. Additionally, they may reference Rarity or Legality ratings - in these cases replace them with Rare (X) and Illegal (X).
For example, a Rarity rating of 8 becomes Rare (8).
So it acknowledges them but doesn’t say anything about going off and using older lists.
The fact that there is an updated Trading Post in this very book suggests you use that - otherwise what’s the point of it being there?
There's no point in saying “when you see a reference to the Black Market in an older publication, go and visit the Trading Post in a completely different book - which doesn’t actually have any Black Market items in it”. Especially when this one in the
Core Rulebook (clue in name) has
all of the BM items in it along with the rest of the TP and it’s now just all called
Trading Post.
All the Trading Post section says is this:
The following pages contain rules for all of the weapons and Wargear available to gangs and fighters through the Trading Post.
Players should note that, unless they are included alongside special ammo types, the various weapons unique to the Clan Houses of Necromunda (such as the advanced las weapons of Van Saar or the iconic polearms of Cawdor) are not included in this list. Such weapons are available only to gangs belonging to the Houses that manufacture them and can be found within the gang's own equipment lists. Such weapons are not normally available through the Trading Post and gangs of rival Houses would not consider using such weapons. These weapons are so closely linked to the cultural identities of the Houses that using such a weapon is simply not done in Necromundan culture. Profiles and rules tor these weapons can be found in the relevant supplements.
We’re quibbling over semantics here again though.
“The following pages contain rules
for all of the weapons and Wargear available to gangs and fighters through the Trading Post.”
“But they don’t include the one from Book of Peril!!”
No, no they don’t. Presumably they didn’t bother putting in rules for anti-plant shells and grenades when there aren’t actually any rules for vegetation in any of the other books other than that one.
It sits back and it’s 2019 Hay Day of being a completely separate list which is to be used
in addition to the regular list. Now, the question is does the things from BoR also still sit as an optional extra plug-in to a regular list or has it been effectively outdated?
The rest of that information in the trading post section in the core rulebook basically just reiterates exactly the same sort of thing we’ve seen printed time and time again, which is that there are various weapons unique (whatever definition that is supposed to be) to various Houses and that they won’t use any weapons from any other House and weapons unique to those Houses are to be found within the publications for those Houses.
The fact they keep using the word House or Clan Houses is actually quite annoying since outside of the main six, everybody else is a faction not a house and it would be nice to know if the factions follow the same rules as the houses - though I think we can probably assume they do.