Crankcase studs/nuts

[CTull]

I am restoring my 1958 Duo-Glide and am having some trouble with details, according to B. Palmers book in appendix C under non year specific, it says “all engine studs and nuts” are parkerized, under year specific it says “ all crankcase bolts” are cad. Looking at some pictures it looks like at least the nuts are cad. Can someone get me strait on this?
Thanks
Craig