Mary Lincoln's engraved opera glasses?

[L Verge]

I would be very leery about the provenance on this and wonder what specifically makes Ed so sure the glasses are genuine. What's the conversion rate to determine how much they realized at auction -- 9000 lb. symbol?

I'm not questioning that Mary might have carried the glasses, or been given them by a White House servant who just thought she might need them. However, multiple pairs left in the presidential box would be questionable, unless Clara Harris carried a pair or even the gents.