It's definitely not commonly known as a derogatory word in English - at least not by the largest English speaking nation (US).
Very, very few Americans would even know any meaning for the word "munt". But if they heard it spoken, especially if in the context of money or the herb (mint), they would assume the speaker said "mint". Also, I don't think it's a bit of a stretch to imagine that munt became mint in England a few hundred years ago...
Some of the people here need to lighten up about names. Perhaps we can start with the assumption that a word isn't being used negatively until it's demonstrated otherwise.
It's both, which meaning comes across is dependent on who you're talking to I guess! Wiktionary says the drug-related meaning is from New Zealand, but it's been around here in London for at least two decades... we do have a lot of Anzacs though!
In high school (so, decades ago), we found the word "tight" as a graffiti piece on the school wall one morning. That was the day I learned it stood for "drunk".
