All four types of designs based on HGUC Gundam UC series' box art. One randomly included I supposed.
As the image on the clear file suggests, this is a special prize for Gunpla 30th Anniversary. However, so far only HGUC ReZEL is listed to have this special prize. Other HGUC kits, including ReZEL Commander Unit and Loto, the already released HGUC Unicorn Gundam and Kshatriya from "Gundam UC" are not included to have this special prize.
A special promotion just for ReZEL? ^^;
HGUC ReZEL will be released on January 22nd at 2,100 Yen (inclusive of tax).
Images are from Hobby Shop Digitamin Rakuten Store.