You really need new Wills. Each state has its own laws, and each is a bit different. Believe it or not, IF and WHEN "something happens" you'd save money for your heirs 5 times over and avoid a lot of hassle for them with new wills tailored to your state's laws and probate practices. They are that much easier to probate and les expensive.
The only exception is if there have been health changes so that someone might question your competence down the road, based on changes since the earlier Wills.
If you can't find the designated executrix, you DEFINITELY want a new one. A new will is likely less expensive than a Codicil to the old Will, but that's a possibility too.
Also, the cost is NOT usually high for a lawyer to do a Will ABSENT significant tax planning. If your estates are less than $675,000 combined ($1 million as of 1/1/02) there will be NO estate tax even if both of you die right after the other. If together they exceed the thresholds you may need estate planning if you are prepared to leave much to each other.
And if there are estate tax issues, the money it costs for lawyer fees now likely will be saved 50 fold as estate taxes are high -- and start at 37% on the first dollar.