For this keyboard, they say it's a canadian english one. Never saw one before so I don't know...
Hmmm, I don't think there's an absolute trick to automaticaly differenciate language and country. The layouts I can recognize are the ones I came across at least once.
I would say a good way to differenciate 2 really close layout is remembering the symbols on the key right under esc (they seem to always change) and the 2 or 3 keys just next to the right shift for complete accuracy.
That's how I do but I don't know if it's 100% accurate.
What would be interesting would be to find (or do) an international layout chart for Geekhackers usage. A big memo of sort, to help us dig ebay