1990 Vanagon GL

After reading a few notes files, I tried the easy fix.  I removed the
instrument cluster, removed the speedometer/odometer from the cluster,
and noted the shaft had just fallen out of the end of its groove.  I
pushed it back in and shifted the lugs (?) over slightly.  As I
expected, it worked for .5 of a mile.

I have an old speedometer/odometer from my 1984 Wolfsburg.

Question: Will this work in the 1990 van?  The unit size looks the
same, however, where the speedometer cable attaches, it looks slightly
different from what I recall when I had the 1990 part out.

Also, there is no printed circuit board attached to the back of the
1984 unit.  However, I think this could be just left hanging on the
back of the 1990 unit.

Comments?