FLT CREW OF B737-300 INCORRECTLY ADVISED ACFT PART RECOVERED FROM LNDG RWY WAS NOT FROM THEIR ACFT. CONTINUED 2 MORE LEGS UNTIL NOTIFIED BY MAINT IT WAS FROM THEIR ACFT. LOCATION OF MISSING PART WAS OBSCURED DURING WALKAROUND INSPECTION BY RETRACTED FLAPS.

Narrative

UPON LNDG IN BUR AND TAXIING TO THE GATE A RAMPER CAME INTO THE COCKPIT AND SAID A PIECE MAY HAVE FALLEN OFF OUR AIRPLANE ON LNDG. I WENT DOWN TO THE RAMP TO LOOK AT THE AIRPLANE WHILE ARPT OPS RETRIEVED THE ITEM FROM THE RWY. AFTER DOING A COMPLETE WALKAROUND; I FOUND NOTHING MISSING. ARPT OPS THEN BROUGHT THE ITEM TO ME. THE ITEM DID NOT LOOK FAMILIAR BUT I ASSUMED IT WAS FROM OUR ACFT. I WAS ABOUT TO TAKE IT FROM HIM WHEN HE STATED THAT PIECE WAS NOT OFF OUR ACFT; IT WAS FROM A CHALLENGER JET THAT WAS ELSEWHERE ON THE ARPT. HE STATED THIS TWICE TO ME. SINCE HE WAS ADAMANT ABOUT IT NOT BEING OFF OUR JET AND I FOUND NOTHING MISSING; WE CONTINUED 2 MORE LEGS. WHEN WE LANDED; MAINT CAME ABOARD AND STATED WE LOST A PIECE IN BUR. THEY HAD TO LOWER THE FLAPS TO SEE WHERE IT HAD COME OFF. WE SWAPPED ACFT SO THEY COULD WORK ON OUR ACFT. WITH THE FLAPS IN THE UP POS ON MY WALKAROUND IN BUR; I COULD NOT SEE WHERE THE PIECE WAS MISSING; AND WITH ARPT OPS CERTAIN IT WAS NOT OFF OUR ACFT; I CONTINUED ON OUR DAY. THE ONLY THING WOULD HAVE BEEN TO CALL MAINT TO THE ACFT TO CONFIRM THE PIECE WAS NOT OFF OUR JET.