The classic Monopoly tokens have not been permanently changed. The current standard set includes the iconic pieces most players recognize. However, a famous 2013 campaign created confusion.
It depends on the edition you buy:
Fact Check: The Iron is currently available in Classic editions. The Cat is retired from standard sets but appears in "Cat Lover's" editions. The T-Rex, Penguin, Duck are the modern "classic" trio.
If you want the 1935 originals, buy a "Classic" or "Vintage" edition. If you want the current voter favorites, buy the standard modern box.