It can (and probably will) be reversed MUCH longer than one week after the sale.
So, buying bitcoins with Paypal is a no risk venture assuming you have good escrow. Selling bitcoins, but getting paid through paypal, is a horrible idea as ANY transaction can be reversed.
You may be able to get your profits from selling BTC for paypal USD out to your bank account (within 1 week) but paypal will put you in a negative balance and they will hire debt collectors to track you down. This does go on your credit if you are in the United States, so look out!
100% guaranteed for the guy buying coins, that's about it.