Not neccesarily. Buddha died of eating a bad ... something. Normally it is translated as "mushroom". But it is often argued that it was pork. (There is evidence to support both view points.) And in fact, quite seperate from this question, there was a great deal of evidence that early Buddhists were NOT vegetarians:
The following link is a decent discussion:
http://ccbs.ntu.edu.tw/FULLTEXT/JR-MEL/waley.htm