No more or less than another of the same date, mintmark, and condition from any other source. I haven't seen their offer, but check with a local coin dealer and see if you can't get a better deal.
That is a very wide range of coins. It is impossible to tell its value.
The melt value of a 1935 or earlier silver dollar is about 0.77 times the current price of silver. Depending on the date,...
A Morgan dollar contains 0.77344 Troy ounces of silver, or about 24.1 grams. The same alloy was used in all Morgan dollars - 90% silver, 10% copper. The coins weigh 26.73 gm when new.
Assuming the coin is circulated and has no mintmark, the 1897 Morgan dollar is a common coin. For an accurate assessment of value the coin needs to be seen and graded. Most coins show a lot of wear....