Heck, if money is a big issue (when isn't it?!), maybe you're right - just get the valves working ok, clean the plugs, put it back together with a new gasket, then figure out why it was running rich.
IF you get it tuned well and running right, I can't see any huge issues with the existing carbon build-up; maybe engine run-on if it's really severe, but I tend to doubt it.
Guess it depends on your short-term plans for the truck. Long-term, you can ALWAYS take it apart again and get it rebuilt when time and money permit. Maybe fix it and drive it in the mean time?
-Michael
