The Battle for Twycross scenario book (which is freaking old) introduced a few classic IS designs refit with Clan equipment known as the (C) series, including the Warhammer, Rifleman, Atlas, Archer, Marauder, Thunderbolt, Shadow Hawk, and Victor. Basically, they were the standard BattleMechs with the weaponry swapped out for ClanTech equivalents or sometimes replacements i.e. the Warhammer (C) swapped it's PPCs out for Clan Large Pulse Lasers. I believe these 'Mechs were designed before the IICs were created as a way of representing Clan second-line troops in the Twycross book, but I'm not prepared to swear by that.
For the Smoke Jaguars in particular, I'd say go for it. As noted, there is some precedent with the forces in the Homeworlds, though even second-line units in the OZ seemed pretty well equipped with Omnis, Clan BattleMechs, and IICs if The Dragon Roars and HTP: Luzerne books are anything to go by. I personally plan on going you plan B route, plopping down a Marauder, Warhammer, etc. but calling it a IIC. Though, having remembered the (C)s, I may use them too. :thumbsup:
