If you can't find the K2 ECS in a catalog, it means the ski was a "SMU," or special make-up. That means it was a generic ski with a special graphic sold to a single ski shop, chain or buying group. Usually the factory's cheapest construction.
I've been out of the mainstream so long that I don't know if factories still do SMUs, but in the day it was a common way to help big-city shops be competitive. Imagine a town with five ski shops, and three of them carry K2, and local skiers have been trained, through years of Labor Day sales, to expect 35% discounts on new skis in September. That means a MSRP of $300 has to go out the door at $200, and to make keystone the wholesale price has to be $100. Joe's Ski Shop promises to match the best price in town -- so if a customer says he saw this K2 ECS for $190 at Bob's Ski Shop, Joe has to eat the $10 difference.
But no one will see the K2 ECS anywhere else. Joe's is the only shop that has it. That's because K2 sells exactly the same ski to Bob's with a topskin that says K2 BSL, and Marty's Ski Shop has it as the K2 SST. They can all hit the $199.99 price point and no one gets undersold. Collusion? No, because Joe and Bob and Marty never talked to each other. K2 is simply selling the same ski at the same price with custom graphics. If, instead of looking at the consumer catalog, you could find the original wholesale price sheet in the dealer's filing cabinet, you'd see the schedule of SMU prices on the third page.
SMUs were commonly sold as a package, with an inexpensive binding built into the price. Inexpensive bindings had plastic housings. Almost all plastics off-gas their volatile components over the decades, which is why cheap old bindings and most ski boots explode after 20 or 30 years (I'd love to find a skiable pair of Nordica GPs but they no longer exist). However -- the race bindings of the era had die-cast aluminum housings and probably are still skiable if used with updated AFDs. I'd happily ski on a pair of Look Nevadas from 1972, if equipped with a new AFD and a ski brake.