unitednations said:not 100% sure. However, you do not even need an unexpired passport for stamping. If you do not have passport or it is expired or about to expire or if you don't want your passport stamped, uscis will give you a document similar to i94 arrival/departure with i551 stamp valid for one year.
joyd said:Nope, not an issue at all! I got my stamping done today and my PP is valid for 6 months, so the officer issued the I-551 stamp only until June'05, by which time I should receive the physical cards.