Buck 110 or LB-7? (Both were really popular big lockbacks at the time). It's really interesting that in these old shows, knives were used as intended, not viewed as some sort of weapon (for some reason, I only see knives used as weapons on today's TV shows). I noticed that in Emergency! the firefighters regularly used what appeared to be either a lot. It was also showed in a bunch of LACOFD training films of the era, so I would assume that it was either quite popular with the LACoFD, or the firefighters were issued that knife.