Carpet install questions

In 1968 carpeted sides were part of an interior package. 1968 only had bottom dash pad. In 1969 the fold down back seat was optional. Each year got progressively cheaper. The 150MPH speedo w/trip came as an interior package, so I don't think you will find a 1968 150MPH speedo w/o a woodgrain dash insert. Locking glovebox was an option.