How to copy a shape to a new layer

Is it possible to copy a snapshot of a shape at a particular frame and paste it to a new layer (without the keyframes)?

For example there is an arm of a person that sometimes is obscured and it moves about. The arm needs to be masked. It would save some time if I could copy a shape from an earlier time and paste to a new layer later - rather than set up a new shape from scratch.

No, but you can delete the keyframes on the layer by selecting the shape and removing all keyframes with the keyframe controls on the right side of the timeline.