GR translation: their typewriter keys chattery as their pearlies

[Paul Mackin]

On 1/5/2012 3:47 AM, Mike Jing wrote:
> P79.30-34   Secretaries in woolen shawls and rubber galoshes shiver
> with the winter cold being inhaled through the madhouse’s many
> crevices, their typewriter keys chattery as their pearlies. Maud
> Chilkes, who looks from the rear rather like Cecil Beaton’s photograph
> of Margot Asquith, sits dreaming of a bun and a cup of tea.
>
> I thought here the "pearlies" refers to teeth, but the wiki points to this:
>
> http://en.wikipedia.org/wiki/Pearlies
>
> which doesn't make sense to me in this context.  Am I right on this?
>
yes