How much does Dumbledore know.

[Tanya Swaine]

No: HPFGUIDX 87062

Was reading GOF again the other day, and this bit of information jumped out 
at me.
Dumbledore had rescued Harry from Moody fake, and was ordering the others 
round.
Before he knew who the fake was, he had Winky sent for, while they waited 
for the
polyjuice to wear off.  That has me wondering, just how lucky a guess was that.

Any thoughts?

Tanya