There is no "making of" documentary of the disc, but checking around online I found out that they built a 40-foot(!) Kong out of aluminum frame, rubber and horse tails but it was so unrealistic it only shows up for less than a minute onscreen. Imagine how the builders feel about that.
Two big animatronic hands are featured prominently, and apparently one of them caused minor injuries to Jessica Lange. Another was presented to director Dino Di Laurentiis and the operator slowly raised the middle finger. Di Laurentis laughed, but the hand froze up and was stuck in this position for a couple days.