My film bodies (all of them) have ISO adjustments in 1/3 stop increments (even when aperture or shutter speed can only be adjusted in full or 1/2 stop increments). The digital bodies I've used on the other hand (which are admittedly few, and old) only support full stop ISO adjustments.
I don't even know what my film body has as far as ASA (it's from before ISO was adopted) but it does have 1/3 stop exposure compensation
My D60 is from 2008 and it has 1/3 stop ISO adjustment. Bodies before that could well have been full-stop ISO, I don't really know since that was the first one I bought. I guess I just assumed that they all did since that bottom-of-the-line entry-level body did. Assumptions are not good ideas so I apologize if I posted bad information.