No. Too much has been put into that. With the mileage most old cars and trucks see, and with most not really being pushed hard, there's really no need to upgrade if the valves are still servicable. Just have them properly reground and you'll be fine.
Now, for a counterpoint of sorts, if you have a valve that's not able to be refurbished, say bent, burnt, or worn out, I would suggest to go ahead and upgrade since it is being replaced anyway, Not much difference in cost. I had mine done,as my engine had several bad valves (including a severly burnt #5 exhaust) for $12 a valve, installed.
