Will my pincode delivery restrictions block an order I create in the admin?

No, orders created in the admin are not blocked. Your delivery-restriction pincodes still stop shoppers from checking out to those areas on the storefront. But orders placed by staff from Orders → Manage Orders → Create order skip that check, so you can take phone or counter orders for any address.

So it's up to you to confirm you can actually deliver before clicking Place Order.

Typing a Pincode in the address section fills in the City, State and Country for you when the pincode is recognised.