It's not in any of the old books. From your books, think of them as sort of Clan dead fire missiles. They do NOT roll 3 die but standard 2. They have a built in Narc +2 on die roll. Their Ammo is per ton and has to be marked as short medium and long range missile ammo per slot.
The Short [High Explosive] is 3 points damage per missile Medium [standard] +2 per and Extendend Range or long range is +1 per missile you find the number of missile hitting {adding 2 to die roll} multiply that number by type used, 5 point clusters of damage on the target mech.
The Introduction date I don't know.
