Thanks in part to this seven year old thread, I removed the dash pad from my '67 yesterday. The nuts came off easily with a little Kroil to make them easier to spin by hand. Laying on the floor, they're easy to see and reach with a deep socket.
It's odd that my dash had a complete second row of mounting holes while the one pictured in this thread doesn't. That row had no fasteners, however. There are 12 nuts securing the pad.
The windshield seal interferes a bit more than slightly with removing the pad. I suppose the extent of interference depends on the manufacturer of the seal as some are "deeper" than others and the drilling of the holes at the factory. I have a Carpenter seal and the left corner of the dash was pretty difficult to pry past the seal.
I used a Sheetrok knife between the seal and pad to compress the seal and a screwdriver under the pad to pry the left stud out of its hole. I also put some dish soap on the seal to coax the pad to slide over it. Some grease on the stud also helped. The dash pad is vinyl fabric glued to a steel base with foam inside. It would be very easy to recover using the vinyl as a pattern.
When removing the pad, avoid pressing hard against the raised vinyl edges or ends as you can crack or deform the thing or make it turn white from the stress.
I did all this to paint and clean 50 years of crud from the area around the defroster vents and to clean the pad edges. A drill mounted soft scrub brush (Made by DrillBrush) with Scrubbing Bubbles bathroom cleaner cleaned the pad. Some paint on the edges came right off with lacquer thinner which didn't hurt the pad. Then I polished it with 303 Vinyl Dressing.
To reinstall the pad, I'll probably elongate the hole or holes on the end where the seal fit tightly against the weatherstrip.
Just figured I'd pass this along for anyone attempting the job in the future. Good luck.
Eddie in Rockaway Beach, NY