Got the email confirmation....highlighted the last paragraph in Red since it appears that they will hold the phone for you but you may be treated with lower priority if you go outside your half hour window
We look forward to seeing you.
Come to the Apple, during the Check-in Window you chose to get your pickup started.
Pickup Instructions
Bring your ID
You'll need your valid government-issued photo ID.
For convenience and quicker check-in, add this information to Apple Wallet on your iOS device.
See a Specialist
Show this email and they'll get your items and help set up your device.
Please review your pickup details below. If you can’t make this time, you can still pick up your order, but waiting times may vary.