Is there a document that states that the 3105PEN7440 is NBN approved?
No, unfortunately there isn't any documentation that clearly states 3105PEN7440 is NBN approved. However, there is a PDF that states the product was designed in conjunction with NBN Co. and strongly suggests it was designed entirely around the National Broadband Network.
See attached PDF.
Some of the main features of the 3105PEN7440 are:
Removable hinged door
Cable entry points: Top/Bottom/Rear
Vented front door for air circulation (specifically for backup power supply air circulation)
Removable equipment mounting panel with grid lines, for ease of installation
Wi-Fi network compatible
Cutout for GPO on top and bottom when recess-mounted