Someone will correct me if I'm wrong, but if you see a 1 1/4" connector pin under the blue foil going into the tachometer side of the cluster as opposed to the blue foil being pinned there, then it is a DOPS, Dual Oil Pressure Sensor, which adds an oil warning buzzer if pressure is too low at 2,000 rpm. That only came on 86+ clusters.

Hey this is like Jeopardy, I think I got that one right ;>)
Dave
--- On Fri, 9/21/12, Jamie Fitterer <fittdog8848@HOTMAIL.COM> wrote:
> From: Jamie Fitterer <fittdog8848@HOTMAIL.COM>
> Subject: Re: Insturment Cluster
> To: vanagon@GERRY.VANAGON.COM
> Date: Friday, September 21, 2012, 3:47 PM
> what is DOPS?
> 
> 
> 
> > Date: Fri, 21 Sep 2012 17:30:09 -0400
> > From: dbeierl@ATTGLOBAL.NET
> > Subject: Re: Insturment Cluster
> > To: vanagon@GERRY.VANAGON.COM
> > 
> > At 05:01 PM 9/21/2012, Scott Daniel - Turbovans wrote:
> > >Look for the DOPS mounted behind the speedometer
> .......that also makes
> > >it an 86 or later.
> > 
> > Bingo.� The '85 had the cavity, but no board
> installed and no
> > provision on the flex-circuit to connect to it.
> > 
> > 
> > >if it's not there ..
> > >then I'd say it was an 85 or a rare Wolfsburg�
> 84 instrument cluster
> > >with tach.
> > 
> > And you can tell which by comparing the wiring pinout
> on the panel
> > connector with Bentley or that .pdf.
> > 
> > Yrs,
> > d
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