Should they be that soon. Not necessarily. They do and will sag after a while . Adjustment and reindexing can be done to get the right height back to OEM specs. I believe that there is enough preload there to be able to reindex them a couple of times withought having to replace them.

The OEM specs actually have the drivers side higher than the passenger side to compensate for the drivers weight so it's theoretically never completely even and level.

If you are sagging and adjustment doesn't seem to cut it then it should be a warranty item if you are still within the warranty period. If you aren't and you have to spring for them yourself then you might look into the Sway Away t-bars . They will give you a better firmer ride as they are a stiffer spring rate and have a little more room for front ride height adjustibility.