There are a few members here with unbound 73's and my friend bought his new in 73' unbound. Bulli is el wrongo....there have been quite a few discrepancies noted with his book over the years and this is an example. 74' saw the introduction of the weird plastic bushing covers for the tailpiece and sometimes bridge bushings. 74' also saw the the bridge pickup move closer to the bridge midway in the year. The unbound ebony board was completely off the radar in 75'.