I have the keys to two tubular locks here, they both seem to have 6 notches around the key. Does this mean it's got 6 pins in the lock, or is there a 7th pin under the bit that turns the lock?
Anything is possible. You should be able to count the pins as they are all visible. Can you take a photo or find a link to on the web? Know what manufacturer or model the lock might be?