I found two issues on opennms-graph.properties:
1) The names of the graphs are not explicit. It is very common that the name of the graph is close or equal to the title of the graph you see on the actual rendered image. I think it is good to be consistent with this.
2) The graph templates for Newts are wrong in terms of RRDtool syntax. These statistics are typically used when Newts is enabled, which means, Backshift is rendering the graphs, but if you want to collect those stats from another OpenNMS machine and store them in RRD/JRB files, the data won't be able to be displayed.