Identity mistakes is possible, but Lin Wang was indeed pretty old even if he didn't reach the age 86.
Lin Wang and General Sun Liren, taken in 1947
General Sun Liren brought Lin Wang to Taiwan in 1947, and then send it to Taipei Zoo in 1951. Is Lin Wang the only one male elephant transferred to Taiwan? If it is, there won't be any doubt.
It's 56 years from 1947 to 2003. Sun Liren was 185cm tall, so judging from this photo, Lin Wang had already been a mature adult. Even we treat it as 20 years old at that time, it was more than 75 years old when it died.
I am also confused, Lin Wang died from cardiorespiratory failure sudden shock, and was not said to lose all his teeth.