Help with UK 1853 1/2 penny

I have 2 of these coins and for some reason there is a weight and thickness difference that I can't just put down to normal wear.
Not an area I have any great knowledge in but apart from one being a counterfeit I can't come up with a reasonable answer.

The coin on the left weighs in at 8.80g & coin on the right 9.56g, there is also a slight difference in thickness but diameter is the same.
9.56g is what it should weigh so is it just a simple case of wear causing such a difference, 3/4 of a gram.
Maybe it's just me but that seems like a lot for a coin that is not showing excessive signs of wear.
Opinions welcome.

I have a few 1853 with various wear. It appears to be wear as some of them are thinner than higher grades.

The position of the numbers in the date is different too, 2nd coin : 8 closer to 1, 5 a bit higher

Tony

Thanks for the reply Lee.
It just seems like a lot to lose due to minor wear, basically 9% which my head is struggling to comprehend
There are other points which Tony mentioned, the neck width looks different, the chin and lower jaw line and the date number layout.
Maybe I am over analysing it and it is like you said Lee, its just my head is struggling a bit.

It is strange looking, isn't it? I see what you mean about the chin, and to me the entire truncation area looks slightly different.

Was a halfpenny worth counterfeiting in 1853?