most of the razors up to early 1900s have at least slight sway on their spines, which means they were designed to have a bit of a smile. that then seems to change and more modern razors have straight spines, but most of them got smiles over their lifetime from honing (both by intention and by incompetence).

if you go on ebay now, you'll probably end up with a pretty good amount of junk until you learn to tell the difference, so it really depends what you're after, and if you have the means and desire to buy the education, which isn't very cheap. the cheapest way is to leverage somebody else's already spending the time, money and effort.