Hello & welcome
Unless you have the box or warranty card in the case, there isn't any external way to tell (Roo, none of my BKPs have a serial# stamped on them, although the last few I've bought were fitted by Feline so I didn't look)
You can make an educated guess from the DCR values, however to be certain you need to figure out what magnet type it has - that'll tell you for sure as Apache = A3, Sultans = A2.
If it's A5 then you still might be left guessing as the DCR values of MMlks, Slowhands & ITs all overlap somewhat - but the tone should be a dead giveaway as those 3 models soudn significantly different to each other.
But I have no idea how you tell what type of magnet it it :) perhaps someone else can chime in...