Yep, it is.
David Bell is original author of calc. 
Version 2.x is maintained currently by Landon Curt Noll , and http://www.isthe.com/chongo/tech/comp/calc/ is maintained by him page.

While http://members.tip.net.au/~dbell/ is homepage of David Bell, which has link to mentioned above page devoted to 2.x and sources of 3.1.