The only accessory Kim Kardashians flashing these days is extra hired muscle, which she brought to her sis Kendall Jenners 21st birthday dinner. It was told that a dressed-down Kim slipped into bash night through a private entrance off the garage, and she was covered by 3 body guards whom she hired specifically for the night. Sources say she shed about $100/hour for each of them ... plus, each sisters personal bodyguards were also on hand.There were only about 20 invitees -- including Caitlyn Jenner, Scott Disick and grandma MJ -- in the private room for the party, meaning security guards nearly outnumbered guests.-WTN