One thing to check -- has she been receiving the dividends or have they been reinvested every year? She should have a 1099-DIV from 2002 for dividends paid on the utility stock. That money was included on her 2002 tax return whether she received it or not. If it was reinvested, she should include all the reinvested dividends in her basis. You can call the issuer of the 1099-DIV to find out if she gets cash or more shares. They might even be able to give you total reinvestment since 1969. Otherwise, you can get dividend info from the library.
In general, if she has 169.000 shares, there were probably no reinvestments. If she has 169.374 shares, she probably has reinvested dividends.