That would be about 59 BTC per ounce of silver, including shipping, correct?
Not quite. Morgan and Peace silver dollars contain 0.77345 troy oz of silver each. Uncirculated, the coins weigh 26.73 grams (0.85939 troy oz) of which 90% is silver.
So 50 BTC per coin calculates to 64.65 BTC per troy oz of silver.