Any jewellers on here?

[ofco8]

I inherited a hallmarked 18 carat gold ring and want to have it re modelled. However a jeweller told me that if I did so the ring would lose it's hallmark and therefore could not be classed as 18 carat gold. Is this correct? Surely 18 carat gold is the same however presented?

Any views on this?

 

[Vegas Seagull]

Would still test as 18c but losing its date may affect the value as may re shaping it