I did pretty much what your wanting to do with the dash. It is best, in my opinion, to do what ever you need to replace while the dash is torn apart. I too didn't have a clock, but I wanted to add one. Found it on Ebay. And they show up on here, on the parts board from time to time.
http://www.ebay.com/sch/i.html?_from...clock&_sacat=0
Now if you add a quartz clock, you'll need to replace your lens with one that has a hole for the stem. There is a web-site that does sell digital clocks, but I wanted to keep mine stock looking.
http://www.classicindustries.com/sho...q=dash%20Clock
You can check out my build thread, but then maybe you have already seen it. But I also installed a new radio and replaced the A/C Control. New dash bezel & lens, all from LMC, which I'm very happy with.