The grip dots are likely made of thermoplastic elastomer, or TPE, as this material often seems to be used for grips of handheld tools. This material can get oily if it comes into contact with oils or solvents, or when exposed to high temperatures .
As mentioned in the comments (that is, on one account), this oiliness is not standard for the Faber-Castell Grip 2001.
You might be able to remove it, as suggested by user fixer1234, with some water and mild detergent, or with some rubbing alcohol.
Using talcum powder or cornstarch you might be able to (temporarily) lessen the oiliness.
The following comment from a forum on digital cameras might shed some more light as well:
The "rubber" pad on the camera bottom is likely made from TPE - thermoplastic elastomer. Basically, it is a mixture of rubber and plastic that can be molded by thermoplastic injection molding machines. Google "Santoprene" for product information.
Once of the things that occur with TPE is oil migration. Rubber contains oil and it will slowly migrate to the outer surface. This process occurs so slowly that it is not noticed unless you have something like a metal plate covering the TPE for an extended period, and/or subjected to heat.
Wipe it clean. It is normal, and no big deal.