if a usb device shows ugen but no umass message

I have a question that I suspect there is a short answer to:

If I plug in a sony walkman device via usb and dmesg gives a message like the following:
ugen0: <Sony Net MD Walkman, class 0/0, rev 1.10/1.00, addr 2> on uhub1
... but nothing about umass, does that mean this type of device is unsupported?
I think not:
The NetMD devices will not show up as a mass-storage device, so that's
another drawback of this format. It will show up as a useable device in
SonicStage and can even be used in RealPlayer.
From here.]

If you are quoting the Bible it in your signature I think there shouldn't be a 'the' there. :) But I guess you might not be quoting the Bible.
As I'm sure you've guessed, the umass driver can't do anything with a device unless that devices implements umass mode. Sony are particularly difficult about this, mostly in support of their Digital Rights Management implementation. I gave up on their gear after I had a Walkman that required their software for loading, even on Windows.
Digital Restrictions Management is the better wording for it.