All 1,111 pieces are on chain from the first block. What is not decided is which token gets which piece. One secret number decides that, and until it is published every token shows one of eight samples.
The number's fingerprint has been in the contract since the first block, where nothing can change it:
0x9b60670474400bede5e93d655c5535d452c50fceeeefd7e0dab88d559dcc6144
When the sale closes, the number is published. Hash it, compare it to that line, and you have checked it was fixed before anyone bought anything.