Black Hawk (Nova) Prime, A, B, C, D, E (p. 70/71)
Daishi (Dire Wolf) Prime, A, C, S (p. 85/86)
Dasher (Firemoth) Prime, A, B, C, D, E (p. 86/87)
Dragonfly (Viper) Prime, A, B, C, D, E (p. 89/90)
Fenris (Ice Ferret) Prime, A, B, C, D, E (p. 93)
Gladiator (Executioner) Prime, A, B, C, D, E (98/99)
Koshi (Mist Lynx) Prime, A, B, C, D, E (p. 117)
Loki (Hellbringer) Prime, A, B, C (p. 121)
Man O'War (Gargoyle) Prime, A, B, C, D, (p. 124)
Masakari (Warhawk) Prime, A, B, C, D, (p. 127)
Puma (Adder) Prime, A, B, C, D, E (p. 141)
Thor (Summoner) Prime, A, B, C, D, E (p. 156)
are all IS General / Merc General.
In contrast from the 16 "classic" ClanMechs the Uller, Ryoken, Vulture, Mad Cat are not marked as IS/Merc General.
Neither TRO 3050U nor an other source claims that every House/Merc unit should have access to these designs (even with ATM technology...). On the other hand no other possible criterion (in production, WD produced, Diamond Shark sell, salvage, etc.) apply to these selection consistently.