You asked if it was the REAL Kirui who ran the Prague half.
Might very well have been. This from the iaaf page:
....A persistent Achilles tendon injury thwarted his Olympic ambitions that year and although he continued to race to a high standard for the next couple of years, it would ultimately end his international career. Even an operation in a Swiss clinic failed to resolve the matter, although he recently made a tentative return to racing, on the roads, running a 65min half-marathon last autumn.
the guy was some runner!!