Sorry, for the delay in replying but I have been ill. It also explains my confusing/confused earlier message. Never write a GMB reply with temperature!!!
To answer your question: the pontil marks are quite different for each miniature weight.... One is quite clean with few radial stress lines but the other is much less tidy with more and deeper marks...
Also, I have a 1930s Ysart concentric (I emailed you pictures of it before the summer) the pontil of which is terribly tidy (a small scar and no radial stress lines) when compared to other Ysart I have seen.
I am not sure that this will help dating the weight accurately though. :pb: