You should look up the place you're getting the comic printed and see what they recommend. Most printers will specify if they use cmyk or rgb printers, and importantly, what model of CMYK they use.
For example Mixam, a digital comics print service in the UK, specifies in their FAQ:
"We recommend you set up your CMYK files as GRACoL 2006 or FOGRA39 or ISO Coated V2 or Euroscale."
This is really good, because these are more modern CMYK models and have a wider gamut than some older ones. That said, when preparing the print proofs of my comic, I've had to check how the pages look under a FOGRA39 proof (you can do this in Photoshop and similar) and then tweak colours, mostly bright pinks, to look better.
