We do not expressly require admin privileges, however it is an easy way to ensure that inventory will proceed without having to do any special configuration.
A service account with access to C$, the ability to run NET RPC, Remote Registry, and Remote (read-only) WMI will work for inventory.
That said, we ask for local admin to make setup as easy for our customers as possible, and some of our inventory work would ideally take place in the local space provided by the admin share (often ‘C$’).
Also, features of Windows such as UAC (User Account Control) and many services such as remote registry, remote WMI, and remote procedure calls are allowed to pass through when connecting as a local admin but are often blocked otherwise.
However, it is important to note that our inventory tool does not expressly require administrator rights.