The eBay listing bills the book as a "family Bible." The book is actually one of Spurgeon's own worksThe Interpreter. This was a family devotional book written by Spurgeon and consisting of selected Bible passages with devotional commentary (much like Morning and Evening). The Interpreter was the largest of all Spurgeon's books and was as large as a family Bible, with similar binding. The signature and inscription on this copy bear all the marks of authenticity.
PS: Not that such statistics mean anything, but according to the BlogSpot counter, this is post #100 on PyroManiac.