Yeah, did a quick search for the Cataphract. It's in the heavy system stores item collection for Liao, not the faction item collection.
The new 'Mechs can appear both in the system store (on the more developed worlds) and the faction specific store, at least for the Cataphract (didn't check the other ones)
itemCollection_major_Liao,,,
itemCollection_systemStores_Mechs_Liao_Heavy,Reference,2,1
itemCollection_systemStores_MechParts_Liao_Heavy,Reference,2,1
temCollection_faction_Liao,,,
itemCollection_systemStores_Mechs_Liao_Heavy,Reference,0,10
itemCollection_systemStores_MechParts_Liao_Heavy,Reference,0,10
itemCollection_systemStores_Mechs_Liao_Heavy,,,
mechdef_cataphract_CTF-0X,Mech,1,1
itemCollection_systemStores_MechParts_Liao_Heavy,,,
mechdef_cataphract_CTF-0X,MechPart,1,1