A highly appopriate gift for an xmarker to give to his lass.
I have to admit that when you mentioned luckenbooth in the thread title my first thoughts were of the Scottish Country Dance called The Luckenbooth Brooch which I frequently practise at SCD class.
http://my.strathspey.org/dd/dance/3980/
Congratulations on your engagement.
Good call to book your lass for marriage without waiting any longer. In my mis-spent youth I dated a girl for over five years then she got impatient and suddenly went off and married someone new. Needless to say after that experience I only courted my first and second wives for a few months before popping the question!
As I see it, no hard and fast rule as whether to give her the Luckenbooth now or at the wedding. If I was in your position, I would be inclined to give her it now as a good omen towards the future marriage takng place and being successful.