Are spatial memory and mental mapping skills the same? I have a colleague that says they are totally different, that spatial memory is a memory and not a skill while mental mapping is a skill because it can be measured with test and tools.

Based on what I read, doesn't spatial memory encompasses mental mapping?
The two key parts of memory are coding and recall, we code information to our spatial memory, and the recall is the mental map and, therefore, part of memory. I'd be curious to see what your colleague's logic is behind their definition for skill, but from what is provided, I'd argue that the distinction of spatial memory being memory because we can't test it, while the mental map is a skill because we can to be in error. The Weschler Memory Scale (WNS) is designed specifically to evaluate memory (and is often a vital part of a neuropsych assessment) and, by your colleague's logic, the tests within the WMS don't test memory at all, but the way we manifest our results (such as how to use a pencil), and, of course, memory could arguably be considered a skill anyway.