Board Thread:Questions and Answers/@comment-112.206.128.133-20160415134638/@comment-91.157.76.247-20160415153528

I'd say yes. There are examples(ish?) of at least  Noble Phantasms ( Skills up to interpretation) allowing their users to harm Servants with things not normally able to do so. The NP example would be Fate/Zero Berserker's Knight of Honor Noble Phantasm, whereas depending on interpretation, Fate/stay night's Berserker's Bravery could allow bare-handed blows to deal damage to Servants.