These are covers from Rex Komiks #4-7, published by Rex Publications, Inc. in 1978, representing a unique characteristic of this title of the time, that of “page one covers”. Simply put, the very first page of the very first story of the anthology comic is also the cover. The cover is not a separate entity from the first page. The cover IS the first page.
I can only speculate the reasons why this was done. The most obvious reason I can think of is the cutting of costs. I don’t know if the artist received simply a page rate for it, or if he received an additional rate because it’s also a cover. Most likely, it was a regular page rate, if the cutting of costs was the purpose.
The trend lasted only a couple of weeks, with the page one covers running only from issue #4 to issue #15. #16 saw the resumption of the regular covers.
A relatively modern equivalent I can think of would be Budjette Tan and Arnold Arre’s Batch #72 #3. Here Budjette says it was done to minimize the cost of printing.
“Dugo ng Aztec” created by Jim Fernandez and Elmer Esquivas
“Batch 72″ created by Budjette Tan and Arnold Arre
Rex Komiks covers courtesy of KC Cordero.