If a boot that looks leather says all man made upper on the tag, does that mean the shoe is fully synthetic?
All man made upper means the entire shoe, except for the sole. So that would mean the entire top of the shoe is definitely synthetic. No leather on the outside, and the lining is not cotton. If the sole was leather it would probably say it was since it would be a selling point. But odds are that if the rest of the shoe isn't, the sole is not going to be leather.
If a boot that looks leather says all man made upper on the tag, does that mean the shoe is fully synthetic?
It most likely is then, just check that the sole isn't leather Dune
What is pebbled leather? Is it better than regular leather in any way?
Pebble refers to the grain/texture,on the surface of the leather. It is not necessarily better or worse than any other leather finish, it's just a different look. What makes a leather more expensive/desirable is the type of skin the leather is and how the texture/grain came about on the skin. For example, if the leather is a lower grade (less expensive split verses a full grain premium skin), and the pebble is embossed/printed on the leather, the skin will be cheaper and doesn't look as good as a full grain skin that is tumbled during processing to create the pebble effect. See image below with some of the more popular leather textures.