32k SIM Card - The Truth?

Greetings,

Thanks again to everyone who responded to my question concerning purchasing
a Motorola T720 (GSM) for use with Cingular. Yes, I did purchase the
phone - it was a good deal - but now I have a question concerning what I was
told by the proprietor of my local Cingular store here in town.

First off, he told me that he didn't carry the 32k SIM cards anymore so I
would have to find one on my own. That's no big deal - however, he also
told me that I would not get good service using a phone with a 32k SIM card.
He stated that the 32k card would not allow my phone to talk with all of the
towers on the Cingular network (specifically the towers they acquired
because of the merger with AT&T).

Was he telling the truth, or is he just blowing smoke at me in order to
convince me to purchase a new phone from him (and get sucked into another
contract, which I don't want to do)?

Thanks in advance for any words of wisdom.

Cheers - Jonathan