I've a 2012 JKU that I bought back in December. Last night I had to pull the carpets and plugs due to some flooding by my Bestop doors not having the greatest of seals. This morning I noticed surface rust building up on the metal visible through the two foremost drain plugs.

 

Dammed phone ...

Anyways, the rust spot is visible in this pic

It's been a fairly mild year, barely any snow so almost no salt laid out ... Should rust be expected so soon?!

 

If the paint/primer was a little thin there from the factory, or if there was a scratch there from rocks or debris allowing moisture under the paint, rust can form very quickly. And sadly if it's not treated properly, it will only get worse.

Any time I've dealt with corrosion I take a scotch-brite pad on a grinder and clean out any signs of rust, right down to the bare metal. Wipe up the area with a degreaser or even rubbing alcohol. Then prime and re-paint the area.

I'm sure there are better methods out there, but this is at least a start and better than leaving it as is.