Inaccurate, or at least incomplete.
Grant owned one slave, apparently a gift from his wealthy father-in-law. He freed him in 1859, at a time when he desperately needed money. He was probably worth at least a year's income for Grant. It is unlikely Lee freed any slaves at such great personal financial cost.
Grant's wife had several slaves who helped around the house. It is not known who held legal title to them. It may very well have been her father, but in any case it wasn't Grant. She stated in her memoirs that they were freed by the Emancipation Proclamation, which of course was inaccurate.
I don't know who took the greater financial hit in freeing slaves, I don't think that's relevant to the point, which is that Lee did free all of his slaves because he didn't want people to think he was motivated by the desire to preserve slavery. And while Grant may have freed a slave in 1959, there were still people of color calling him “Master” at war’s end.