I have a Ont HG8546M, and GenieAcs dont show all parameters about configuration, more exactly, wan interfaces. On the Ont have 3 wan interfaces, but Genie only show 1 wan interfaces.
But doing clik on Refresh in Devices, then of a few minutes appears all rest information about parameters.
GenieACS does not refresh the entire device data model. Doing so is incredibly inefficient and time consuming. You can use provision scripts to refresh the data you desire.
As akcoder says, if you want to read certain parameters that are not reading at bootstrap by GenieACS, you need to create a preset or provision to do it and read values that you need.