While installing new sleeves and pistons in our 3196 CAT engine I discovered that one rod had two indentions for the rod bearing even though all the others only had one.  Piston and sleeves look and fit right but I noticed the piston had a different CAT part number as I was preparing to install the head.  Wondering if I made a mistake by installing the sleeve/piston assembly since it doesn't "match" the other five.  Do you think someone gave me a wrong piston assembly?  I'd hate to ruin a good overhaul by installing the wrong part.  Should I be concerned about the difference?

   Thanks.                  Dan