I suspect not as the rail gauge looks wider than the 1 metre gauge used in Borneo. Also Borneo rail Jeeps had smaller diameter wheels. It looks closer to 3'6" gauge used in mainland Australia. I'm looking at the off set of the wheel hubs to make this observation.
The photo below is also metre gauge but in Malaya not Borneo which used much larger diameter wheels than used in Borneo.
photos (162) by
tankienz, on Flickr
Hidden under an improvised armoured body is another Malayan Railways rail Jeep.
These rail Jeeps were used by Commonwealth Army's patrolling rail tracks during the Malay Emergency.