Yes, exactly.
"And, the dispersion of olivine across the martian surface suggests that the climatic conditions that allow for its existence have been pretty much ubiquitous for a very, very long time."
Glad you mentioned that! Because we would expect the olivine to be dispersed over the Martian surface the fact that it is NOT found on 98% of the Martian surface strongly implies that these areas HAVE been subjected to aqueous weathering.
Bob Clark :-)