Highly likely this is a complete scam. If you want to look into the will, you can do that or hire an attorney to look. NO WAY this does anything other than smell.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.
Check out this site. If there really is unclaimed property in your name, you can get the info without paying a fee.