According to the manual, yes. According to my experience with multiple iMacs, no.
Perhaps I am just not bending stuff enough? I don't know, kinda scared to use more force as _all_ of the the plastic in G3 iMacs is not at all known for quality and durability over long periods of time.
*shrug* I have even tried using very small thin objects to pry the tab while I slide the speaker off with no success.