Massallah pertaining to paying back stolen goods

AssalamuAlaikum MuftiSaab
May Allah reward MuftiSaab for the good work you are doing.
A person stole goods a few years back and sold it for R10 000. The value of the goods was alot more but he can’t remember now what the value was back then. Must he give the amount of money that he sold the goods in charity the R10 000 or the value of the goods, and if so how does he calculate the value of the goods back then?
jazakallah