Dan did mention the small gaps in the Res-C. At least the sizing ones for different designs. I haven't read any reports of problems with rusting from any infi/res-c handle gaps. If you decide to keep and use it and you're worried you cen fill the gaps with something.
The Gaps only go back about 1/16 or maybe at most 1/8 inch. Dan showed a pic of how to trim them off but I don't remember where.
