The CR2032 batteries have not arrived yet, but I also ordered CR2450 batteries the same day from a different eBay US source.
The CR2450 batteries just arrived. The unpadded cardboard envelope has two five-pack strips of CR2450 button batteries inside, which are larger and thicker than CR2032s.
The back of the envelope has a large sticker that says: "UN3090 - For more information, call: 800-424-9300" and "Surface Mail Only Lithium Metal Batteries Forbidden for Air Transport" UN3090 is a dangerous materials code for lithium metal batteries. The 800 phone number goes to a company called Chemtrec. It is their "Emergency Response Line."