I'm looking to replace the tach-less cluster on my 91 standard civic hatch, manual trans, with a cluster having a tach. Swapping an auto trans cluster is OK, but a manual one would be better.
I have learned that for a simple "plug and play" swap I can use clusters from:
1990-1991 CRXs (DX,HF,and SI) and
1990-1991 Civic Si HBs.
Am I on the right track with this?

In searching for clusters on ebay, there seems to be a lot of disinformation about compatibility and what models the clusters were pulled from.
The part numbers I obtained from Honda dealer sites don't appear to be exactly the same as those that appear on the clusters.
Does anyone know the real part numbers, (78100 - SH3 - ####) or (HR - ### - ###), that appear on the clusters that come with the models listed above?
My best guess so far is 78100-SH3-L100 are manual trans clusters from 90-91 DX, Si, and HF CRXs and Civic Si Hatchs, and 78100-SH3-L000 are auto trans clusters from 90-91 DX CRXs.
Any help you can give me will be greatly appreciated. Thanks in advance.