Yeah, you can probably fix it with the end caps, if you have them. I like the washer trick.
Or you could look for some type of adjustable foot (like a caster only without wheels) at the hardware store that would fit in the pipe leg.
Or you could put a thin shim (or wood scrap) on the top end of the legs where you screw them into the underside of the table. Something to make only leg sit a little further below the other.
Or glue a penny to the bottom of the leg/foot. Or how about matchbook, it works at the diner.
