Hi there, I was just getting around to reading the BR Leader this morning and saw your horse shoe. As far as I can tell, it is a pretty standard draft horse shoe.
The reason I would think it is NOT a mule shoe is two-fold. First, mules tend toward having oval shaped feet, not perfectly round as your shoe measures. The other would be that large mules may have likely remained unshod, even in work, being famous for having tougher quality feet, and perhaps also for being famous for their opinionated nature and kicking talent.
I think it is more likely that you have a standard draft horse shoe there. The tabs are called clips, and help hold a horse’s foot together under stress, and maintain position of the shoe, reducing the possibility of the shoe loosening and/or coming off prematurely. The bolts are probably called caulks, and are used to give the horse an unnatural level of grip in slippery conditions, much like the cleats of a field sport shoe for humans.
Also, in our area, the soils are deficient in several trace minerals that help a horse grow a healthy foot, resulting in draft horses, in particularly, growing a poorer quality hoof that does not maintain integrity under working conditions. If this were not so, the drafties might not need a shoe at all. With today’s knowledge, we are able to supplement horses to account for these regional mineral deficiencies, and thus help them to grow a healthier foot.
If you find this helpful, you should consider checking my opinions here with a local farrier.