Linn Akurate 242 version?

Over the past 25 years, I've owned a lot of Linn gear.  I've always really loved their speakers and recently acquired a pair of Akurate 242's.  I'm trying to determine is they're a Mk.1 or a Mk.2.  They appear to be later models but is there an easy way to determine based on the serial numbers?  Mine are 957xxx.  Any information is appreciated.  Cheers!