Is Bob Fitzsimmons still a top 30 all time heavyweight?

IIRC Sharkey got a gift with that draw against Corbett too.

 

A person can be considered in a certain weight class either because :
1) it is the class immediately above the highest weight limit he or she cannot go down to while remaining competitive;
2) it is the highest class in which a person may be competitive against opponents of comparable professional standing.

Bob Fitzsimmons, in as much as he was for many years competitive and successful in the unlimited weight class (heavyweight) may, by consideration 2), be considered a heavyweight, and a great one by a moderately broad sense of 'great'.