This is why I like Theories of Surplus Value so much. It was going to be volume 4 of Capital but Marx died before Volume 2 was even finished and Engels died before compiling volume 4 from Marx's notes. Eventually Kautsky got a hold of these notes, but his edition of Theories of Surplus Value is no longer in print. Then Riazanov in the Soviet Union bought them from Germany just in time to avoid them getting burned by the nazis. He compiled them into a serviceable 3 volumes. Theories of Surplus Value is basically Marx going over all the famous European bourgeois political economists leading up to him. He goes over the French physiocrats. He goes over Adam Smith. He goes over Ricardo. He goes over Malthus. He goes over Mill. He builds an entire history of the concept of Surplus value (i.e. unpaid labor, i.e. exploitation) and how it was understood and misunderstood prior to his writing capital. I wish he had lived long enough to actually give us the full version. Marx's take on Adam Smith is that he basically figured out surplus value, but couldn't grapple with the concept properly, and thus "reverts" to being a "mere physiocrat" in much of his writing:

Quoting Marx talking about Adam Smith:

Adam Smith very acutely notes that the really great development of the productive power of labour starts only from the moment when it is transformed into wage-labour, and the conditions of labour confront it on the one hand as landed property and on the other as capital. The development of the productive power of labour thus begins only under conditions in which the labourer himself can no longer appropriate its result. It is therefore quite useless to investigate how this growth of productive powers might have influenced or would influence “wages”, taken here as equal to the product of labour, on the hypothesis that the product of labour (or the value of this product) belongedto the labourer himself.

Adam Smith is very copiously infected with the conceptions of the Physiocrats, and often whole strata run through his work which belong to the Physiocrats and are in complete contradiction with the views specifically advanced by him. This is so, for example, in the theory of rent, etc. For our present purpose we can completely disregard these passages in his writings, which are not characteristic of himself, but in which he is a mere Physiocrat.