This is not true.......Wolfsburg editions in 84 had the TACH.  and so did other versions in 85.   

> Date: Fri, 21 Sep 2012 13:52:10 -0700
> Subject: Re: Insturment Cluster
> From: tom@carchrae.net
> To: fittdog8848@hotmail.com
> CC: vanagon@gerry.vanagon.com
> 
> The 84-85 don't require the modification.... because they don't have a
> tachometer.    :)   Wish it did, but the instructions to add it scared
> me off.
> 
> So, your cluster must be >86
> 
> 
> 
> On Fri, Sep 21, 2012 at 1:36 PM, Jamie Fitterer <fittdog8848@hotmail.com> wrote:
> > Hello,
> >
> > I have an instrument cluster I bought from someone off the list YEARS ago.  Thing is, I can't remember if it is  84,85,86 cluster.  It has  TACH.  any way to know what year it is from?   The reason I asked is I have a bostig conversion and want to upgrade to this cluster to get the TACH in dash.  I also need to know if 84,85 or 86 as 84 and 85 do not require Bostig's TACH modification as the 86 and newer does.
> >
> >
> > Thanks
> >