Novice user with really easy question regarding atheros compatibility on 3com wireless card

Hi all.. Novice user, but I love BSD and any free OS compared to Windows,
but I have a pretty easy question regarding a card I am about to go out and
purchase.

Right now I have a Dell D600 Laptop which uses a Broadcomm BCM4306 wireless
card (which makes setting up wireless a REAL pain under any OS other than
Windows.)  I am totally sick and tired of always having to use a NDISwrapper
tool to use 3rd Party windows drivers, so I want to go out and buy a much
better wireless card that will work without me having to do so much manual
configuration..  I just want the thing to be detected and ready to go when I
install things like FreeBSD or Linux..  (Obviously mainly FreeBSD)

So I visited the hardware compatibility list at
www.freebsd.org/releases/and checked for cards with the ath(4)
compatibility (EVERYONE on #freebsd on
irc.freenode.net reccomended getting an Atheros card).. My selection of
cards here in Canada is quite limited, but luckily according to the hardware
compatibility list it says "3COM 3CRPAG175"

Here at my local store I was able to find THIS CARD:
http://www.compusmart.com/Product/Default.aspx?CatalogID=0&SupplierPartNo=334098&ShowStoreInv=True

But the Part # has an additional letter than the one on the compatibility
list!  This PART # is "3COM 3CRPAG175B" (note the extra B on the end)..  Now
generally I would think that it wouldn't or shouldn't make a difference and
its probably just a revision or something, but this is alot of money to blow
on a card if it isn't backwards compatible.

I desperately need a bit of help knowing if this card is going to compatible
with ath before I go out and drop $119 on it, so if ANYONE could help get
the information or the answer I need it would be GREATLY appreciated

Thank you so much in advance, I really appreciate help on groups like this
as a new user :)

Seeya
-Ryan