yes some did have fans buried deep in them, but aside from the first couple generations, I couldn't tell you which ones
and they still ran quite warm, at the time I figured where it was could not be effectively cooled by convection so they had to move some air one way or another, they choose a slow moving fan

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ALL Tray loading iMacs (the original 233 Mhz Bondi iMacs, and the first Rev. C/D (266/333 Mhz) fruit flavoured models) had fans in them, it wasn't until the slot load iMac/iMac DV/iMac DV SE came out in late 1999 that they went fanless.

And yes, even the tray load iMacs with fans do run very hot. For the past two summers I've actually run my iMac 333 with an external display, that way the internal display remains off and the system runs much, much cooler, so cool in fact that the top of the machine feels just as cool as it would if the machine had been off, even after running all day. I started doing it in Summer 2008/2009 when I became concerned about how hot that machine gets during Summer. This Summer its been running with the external display since November, and it'll probably stay that way until the end of this month, or whenever the climate cools down a bit.