I got the cover that's on my '72 from J.C. Whitney at least 8 years ago, and it's been in the Oklahoma sun every day since with no cracks, fading, or warping. If your dash is uneven underneath take a utility knife to it and straighten it out.
But, like others have said, this is a work truck. If I was doing a resto, the pads from the board vendors are very reasonable, if a pain to install.
SSOW