I have no clue why you would want to do 1999 your first playthrough. I understand wanting to get a little challenge out of it, but that's what hard mode is for. They're practically saying "I wouldn't" by masking it behind a code.
Why not just take in the game the first time through? Enjoy the art, dabble with different weapon upgrades.
Of course, do whatever. I just wouldn't want be my first encounter with the game to result in pulling my hair out.
Because I just find the specialization style of play to be much more interesting. It's an easy decision for me to go with 1999 mode right away,
especially on a first playthrough, because first impressions can color your perception of a game forever. I'd rather think of 1999 mode as basically the default, and only, experience. I did the exact same thing with XCOM and hardcore mode.
Besides, at the end of the day, Infinite is largely a shooter. I can't imagine there will be a point where you've fucked up your character build so hard that a certain sequence will be impossible to get by. You should be able to brute-force your way through such obstacles via mechanical skill and tactical awareness and just Quake some fools.