Hi Graham,

I'm Afraid that there are two holes in the lid which are used to thread the leather thong which hold the antler in place.
If you can cover or live with that It should be no problem.
You might be able to find a fastener more that you are used to which would cover the holes.

Or:

I could always remove it and sand ( This smells a bit so do it outdoors) the horn thinner That might work.