the buckets were part of the CST package in 67
gearing should be 4.10 as standard when v8 and automatic was ordered.
your 67 only CST horn button is missing, and very hard to find looks like this;
Instead of the normal one;
the speed warning was in fact avalible till the end of 69
You have a VERY desirable truck there... esp considering it is so close to being complete... even the oil bath air filter is still there... THAT would be a tough one to locate... they were all thrown away in the 70's.