can I use the wrong year shock?
 

I am wondering what the result will be from using a 72-on shock in 67?
The chart says 67-71, then 72 on.
What torsion bar changed from 71 to 72, and if so, what result does that have on the shock need?

Any help, the reason being I have brand new set of 72-on shocks and wondering how they will work out on my 67.
thx in advance!