Variety North Borneo???

Hi, i'm Sam from Malaysia. I'm a new collector, currently keen on North Borneo and Malaya stamps. However, due to the age of these stamps, some appears to be different but i'm not sure whether it should be treated as variety or not. I hope the community here can shed some light for me.

The above stamp is from North Borneo, with an overprint of 5cent on 8cent, but there seems to be an extra dot above E of CENT. Is this a possible variety?

sam,quite a misplaced overprint over there.i think this is known as DOT variety but no special value.