Are those sentences the same meaning?

1: I was walking alone in the dark, when someone suddenly tapped me on my shoulder.

2: I was walking alone in the dark, when someone suddenly tapped my shoulder.

Question

Are those sentences the same meaning?

1: I was walking alone in the dark, when someone suddenly tapped me on my shoulder.

2: I was walking alone in the dark, when someone suddenly tapped  my shoulder.

Answer

I agree with Roger. There's no difference. We know who - me! We know where - my shoulder. We know it was sudden.

Let me try another. I was walking down the road when all of a sudden someone poked me in the back with an umbrella/poked my back with an umbrella. Hmm. Back. Prod. Umbrella. No, can't see any difference!

Answer

Either one works.  There is no significant difference between the two.