Pay $10 for the Gold Edition of the game, have the guns on the disc
Buy the Standard Edition, hit the max rank level of 25
In both cases, "You have to do the marketing programs that we're going to announce further ahead" (huh?) before you can get the guns.
The last bullet point up there confuses us. What are the marketing programs? Troedsson told IGN there would be five marketing programs from EA that are free and will reportedly be "as easy as signing up for a newsletter." In other words, don't expect the Gold Edition guns on launch day, but know that you can be at rank level 4 and still get access to them at some point.