Quote - "would a rock chip sample that had been mildly exposed...

Quote - "would a rock chip sample that had been mildly exposed to the elements typically have higher grades of lithium content as opposed to a sample that had recently been unearthed."
YES, normally - a sample exposed to weathering would see the leaching out of softer material leaving a higher grade in the remaining part of the sample. Certainly this is true of harder materials such as copper etc. I must confess though, that I have no idea how the lithium contained in whatever form it is in spodumene compares with the surrounding material.