That hasn't got the interstitial plate. In fact it has me baffled, as the faceplate is the part below the line and should not be moulded to the top like that seems to be. There should be a load of stuff in the backbox.
See this page
showing it assembled and disassembled. In particular the top and bottom pictures.
Does your fully assembled setup look like the top picture? Or does it look like the bottom one would if assembled to the backbox without the bit the yellow arrow points to inserted?
Kindness isn't going to cure the world of all its awfulness but it's a good place to begin. Daisy Ridley.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - AAISP Home::1 80/20. Sync 54999/14466Kbps @ 600m. BQMs - IPv4