Heya OH80 good to hear from you.
Hehe...I've considered dates but in the various BCMs I've looked at I've seen numbers higher than 30 in this group of numbers so but I'm not sure it means a date. I just can't seem to find any references anywhere that define what those numbers actually mean. I'll keep looking. I bought the bcm anyway for $60 bucks (they've dropped in price since last year) I'll post up if it works.

[update] My XF's build date is March '04 so that doesn't match the numbers on my BCM.
Hope you're well my friend. Cheers.