I was told by the salesman that if there was a 3G signal which there is, you could pick emails up and asic web browse.
That's correct. 3G is 3G, so as long as you've got roaming enabled and you're roaming on a 3G network, you should be fine.
Are there many other countries with 3G that the 3G Kindle does allow web browsing?
Visited Amman, Jordan recently
You've answered your own question.
It's not exactly a secret that certain countries have implemented certain mechanisms to filter. Often cited case is China, but there are others too, especially in the region you visited.