Yup, looks like a mink!
Self (H/H) x self (H/H) should normally always give 100% self (no markings), but I have heard of some tricky genetics (not on the h-locus) that supposedly can allow markings to pop up out of unmarked parents. I don't really know much about those, and my understanding is those genes are uncommon in the pet population. I know a certain degree of white can be seen on the toes of supposedly genetic self rats, and is fairly common, but that white shouldn't extend past the toes or onto the belly (would then make the rat Irish, Berkshire, or whatever other names people are giving them these days). Briefly I worked with some funny markings quite some time back, I would have to dig up those records to see exactly what I had and what I produced. I don't think those parents were actual genetic selfs though, as I recall them having some small white spots on their belly and white feet.