On Wed, 27 May 2015 18:48:35 +0100
Wols Lists [off-list ref] wrote:

Just for info, I've done an ls -al on my by-id directory, and I have
no clue whatsoever as to what the serial number is. All my drives
appear twice (Seagate Barracudas), there is no manufacturer name that
I can see, and while the model number appears in one of the records,
there is nothing obvious to indicate whether what follows is the
serial number or whether the serial number is part of the other
directory entry.

Not helped, of course, by the fact I have no clue what the serial
number looks like ... :-)

ata-ST3000DM001-1CH166_W1F4JWRP -> ../../sdb
ata-ST3000DM001-1CH166_W1F50K0F -> ../../sda

From a picture of this model's top side
http://www.nix.ru/autocatalog/hdd_seagate/126689_2245_draft_large.jpg
the serial number on this model is 8 alphanumeric characters, so in your case
W1F4JWRP and W1F50K0F are the serial numbers.

-- 
With respect,
Roman