1966 Penny error or just wear?

[Digger54]

Hi. Finally got around to sorting and rolling a large collection of pennies. I recall there was error with 1966 so I held off all the ones as I sorted. I noticed on a couple that the number one in the date was skinny at the bottom. Are these errors or just wear?

Here are three that I found so far with odd looking 1 in the date...

 

[l.cutler]

There are always going to be minor differences between any two coins, different dies, different levels of die wear, dies get polished, coins get damaged and wear. Small anomalies like this really aren't anything special. Errors aren't really year specific, they can happen on any date, mintmark or denomination.