Wait a minute...these came as coils...
Yes indeed and the coils were not available at post offices, you could only get them the Cave. From USPS..
Stamp Fulfillment Services will not make an automatic push distribution to Post Offices. These stamp coils will only be available through The Postal Store®website at usps.com/shop or by calling our toll-free number at 800–782-6724
So the low print quantities and this limited availability might make this a better stamp to collect than normal.