At first I thought this was an "M", what with the bar under the letter. But then I concluded "W" because of my auction and research:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=6100399660

I'm still not convinced about the M or W. Nice inlay monogram anyway. (I have more to sell by the way -- one chip or a set, say $8 each postpaid-insured.)

Robert