ABS on trailer - Missing 49 CFR 571.121

So here is the question, I have a 2001 trailer (Roadrunner Hay Squeeze) it was manufactred after this law

"
S5.2.3.1(a) Each semitrailer (including a trailer converter dolly) manufactured on or after March 1, 1998, shall be equipped with an antilock brake system that directlycontrols the wheels of at least one axle of the vehicle. Wheels on other axles of the vehicle may be indirectly controlled by the antilock brake system.

(b) Each full trailer manufactured on or after March 1, 1998, shall be equipped with an antilock brake system that directly controls the wheels of at least one front axle of the vehicle and at least one rear axle of the vehicle. Wheels on other axles of the vehicle may be indirectly controlled by the antilock brake system.
"

Well mine doesnt have it . At all.

Here is my question - what will be a possible outcomes on a dot inspection

 

Not sure why it doesn't have one I overlooked that . and noticed it after I PAID for it

I haven't called manufacturing yet, will do on Tuesday.
Local shop said it will probably cost me around 2500

So mad at my self

When asked previous owner he said nit to worry about it that is how he drove it for the past 10 year

 

What's "air operated abs"

Thank you.

 

Did you ever had trouble passing inspection?

And what do you mean by 8ft added ? What's you length now

Thanks