Bryston 3B questions

Hi there, I just purchased a Bryston 3B with balanced inputs. On the back, it says to use a min of an 8 ohm load. My speakers (KEF C55) are 6 ohm, is this going to be a problem? Also, is there a way to date this amp by the serial #?
The bryston will be fine with a lower load. I don't know what the back is talking about. I have a 3B and never had any problems. I was looking at some Totem Mani-2 once and Bryston said it would be fine even at a 2ohm load.

As far as the date email James Tanner at bryston and he will be able to help you out. They have a 20 year warrenty from the date of manufacuring. I am not sure how old your amp is. If its getting old I would send it back for a free servicing.