so yeah, the site has basically been down for a month. it's back up now.
The driver available from Linksys also works with BCM4323 dongles and is probably the latest such driver available from Broadcom.
Appears to be manufactured by Wistron NeWeb. DNUB-C1 is the model mentioned on the sample label provided to the FCC.
"48DNUB0E.SGA" and "Manufactured for CISCO" are silkscreened on the board.
This device cannot be used with brcmfmac as the chip revision (r2) is unsupported.
brcmfmac log dump
[ 4287.620388] usb 1-3: new high speed USB device number 10 using ehci_hcd [ 4289.100334] usb 1-3: usbfs: USBDEVFS_CONTROL failed cmd mtp-probe rqt 128 rq 6 len 1024 ret -110 [ 4289.184067] brcmf_usb_fw_download: unsupported chip 43236 rev 2 [ 4289.184080] brcmf_usb_attach: failed! [ 4289.184143] brcmf_usb_probe: failed with errno -19 [ 4289.184258] usbcore: registered new interface driver brcmfmac