1977-How do you remove the instrument panel cover?

[PugDad]

1977 Cheyenne. I need to replace a faulty temperature gauge.

I have the original 1977 Truck Service Manual, no help in there.

I removed all the screws from around the face of the instrument cover, but I cannot remove it. The vent body on the upper right corner won't clear the dash frame.

First question: Am I going at this the right way?

Is it covered in a Chiltons, maybe?

I thought this would be a straight forward process, but it's not turning out that way...do I need to drop the steering column?

Thanks in advance for any suggestions.