Galle fort was extremely interesting to visit and I enjoyed my day there.One scam to watch for is people selling old coins purported to come from ship wrecks.It is against the law in Sri Lanka to remove artifacts from wrecks that are 100 years or more old. This alone should make you wary.
The coins are nicely corroded to look like they are from the sea but in the days when anyone can look up the value of coins on the internet why would anyone sell a 1641 Dutch silver dallaar worth over $300US for $20-$27.
The coins are fake so don't get caught.