i'd try to locate the rattle first. if you have to, get some else to drive while you look under the dash.
removing dash pad is a hassle. some 10 nuts to be removed. the cluster can be brittle and be sure to put a rag or cloth on the column when removing it.
is it something in glovebox? wiring harness or heater box related item?
i doubt its the dashpad itself.

just my thoughts as i have removed and replaced my 67 unit.

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This ain't no L-Kamino!