And you are equally as likely to have just as many people tempted away from you to go for another set of pre-order items as you are to get people to come to you. The whole thing cancels itself out and just leaves a stupid imbalance in the game for no good reason because everything you did didn't take into account these items. I believe you are right that they're attained from a quest a little time in, but it will still have a noticable effect. It also works against you by bottlenecking you into a certain playstyle all the time because you lose the benefit of the gear trying other methods.
Whats the GEP gun got to do with it? That choice was a farce anyway. Options are, Mini-crossbow, found on at least 5 enemies on Liberty Island, including one of the first enemies you come across right outside the entrance. Sniper Rifle, found on 1 enemy the other side of the main entrance. Or the GEP Gun, found several missions later, your only real ranged defence against sentry bots and all around 'door opening' tool. The first bot its easy enough to take it out by sticking the EMP grenade from the UNATCO satcom thing on its patrol route and theres always a steady supply of ammo that will never exceed what you need it for (its useless against infantry because theres no corpse to loot).
Its set before so inflation doesn't mean much