First of all, any qualified appraiser can perform an appraisal as of any date. They use public records to determine comparable sales, making adjustments to equate the subject property to the properties that were actually sold. So that would not be a problem.
However, I am curious as to what your object may be in terms of making a re-determination of the value as of your mother's date of death.
If you are talking about possible adjustments to your prior year tax filings to reduce your income taxes, that would not now be possible in terms of the 2002 tax year. Tax year 2002 has "closed" a long time ago and may not be re-opened, unless for example no tax return was ever filed for that year. Tax years generally close 3 years after the related income tax return is filed, which means that the 2002 tax year would close in 2006 on the comparable date in 2003 that your 2002 income tax return was filed.
If more than 25% of your gross income was omitted from your return, the IRS may re-open that tax year to access additional tax, penalties and interest.
Do you have some other objective in mind? Since appraisals have a significant element of subjectivity to them, it would be very difficult to prove (in a Court of Law), any lack professional standards on behalf of the original appraiser. Any recovery would have to come from him, on some basis, not the IRS since the related tax year is closed.
If your objective would be to seek such a recovery from the original appraiser, then first you would have to determine if that Appraiser is even alive, and if so, the extent of his resources, and finally whether their is any basis for a lawsuit including whether or not the Statute of Limitations is still "open" for whatever aspect of the law he may have violated to your detriment, since you presumably relied on his work in the process of preparing the income tax returns that generated the large income tax bill on the sale of your property.
I expect that the related legal costs of pursuing these issues would be substantial, but it would make sense to me to meet with an attorney to discuss whether or not you even have the ability to pursue whatever aspect you are considering.
I don't see any possible remedy that you would have with the IRS, unless you have not filed your 2002 income tax return.
I'd be happy to respond to any follow-up questions you may have.