if it where me mate id be trying to get the problem sorted , only for the very very slim chance that you may one day end up having an inspection , than it would be an even slimer chance that someone there might know what there talking about and recognise it as not being a darwin and it could then possibly cause problems down the track , not a major problem but wont hurt to sort it now rather than later as
i only say this as i inherited some firearms off my dad and when i did they made a mistake on the paper work and had a pump action 22 rifle registered as a completely different gun , i didnt do anything about it but when i finally got an inspection thats when the problems arose , it all got sorted as it was their mistake but i had to prove to them that it was their fault in the first place