The July 1st 1991 is the NAM-1975 release date
for sale purpose.
This game, as well as other Neo launch titles, was already available in April 1990 as a "not for sale" but rental only game.
In fact, if you check carefully the spine of the older Neo-Geo AES games, you will find that some, under the Neo-Geo logo, have the word "rental" written in japanese katakana, meaning that the first batch of AES were intended for rental only and not for sale
Then, when SNK decided to switch the system from rental to sale, they re-released the games in July 1st 1991 (initially in carton boxes version and then back to the plastic ones that we all know well)