You are right..
A few more precautions..
The phone number of these guys are routed from Europe to Africa. If you make a call you can witness the extra time for redirection and the voice being heard as if from down the well.
Also they will give you an European bank detail which is mainly an offshore bank whose account is linked somewhere to Africa.
Double check with the bank and ask if the account holder is a native of the country he have mentioned.
You can find out the culprits from their language, Call them directly and if you smell any foul drop the deal.