Welcome, and good question. What year cab and clip? I guess you know the differences between 47-53 and 54-55-1st series?
The 47-53 had different speaker grilles and different gauges between Chevy and GMC. Of course those can be changed/swapped. The 54 and 55-1st series GMC had an entirely different dash from Chevy. https://www.stovebolt.com/gallery/images/hoover_dave_1954c.jpg


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