1723 SSC sixpence - 3 over something?

[Paddy]

I was just comparing my various 1723 silver coins  when I noticed something odd about the 3 in the sixpence date.

I checked ESC, which mentions a 3 over 0, but this doesn't look anything like that. 

Any thoughts?

[Coinery]

I’m not overly familiar with the numerals and serifs of the series, but is there any possibility it’s die-fill, or does that throw the shape of the number too much?

[Paddy]

That could be a good shout. My 1723 shilling has damage just at the critical point, but here is the 3 from my much better half crown. I can see that the sixpence 3 appearance could be due to a chunk missing.