Why do you compare works of the law with works produced for temporal gain? What temporal gain is to be expected for, say, loving one's neighbor or obeying one's parents? I assume you would put actual or quasi-altruistic works in the category of those that are salvific, however, my examples are often (but not always) done for that reason and so how can we make a distinction? I don't see any Biblical distinction being made. For example, I might obey my father and mow the lawn. It could either be because he asked me to, or because we agreed he would pay me $20. In either case I am obeying the Law, but no Biblical distinction is made as far as I can tell between one being salvific and the other not. The point of Gal. 2:16 is that neither of these cases is salvific but that it is faith that matters.
Exactly: acts of love such as love toward our neighbor are salvific works, the "good works that we should walk in". If one does it because there is a law compelling him then it ceases to be salvific and becomes something done for a temporal reward.