What Is My Pony
First you have to make sure your pony IS a Hasbro brand My Little Pony. There are many toys that were made to emulate the popular toys, commonly referred to by collectors as Fakies. The most certain way to know is to check her feet, or the bottom (of a sea pony or similar). Is is not 100% however, some toys from the line don't have any markings on them, and some ponies made in other countries may have another manufacturer stamped on their hoof (such as????).
Once you have determined your pony to be indeed a My Little Pony you have to figure out which generation she is. The way to figure this out is to again, look at your pony's feet.
- A G1 pony's copyright date will be between 1982 and 1995. You can see the bottoms of Blossoms feet are slightly concave, she is a CF version of Blossom. The first set were FF ponies, and Hasbro made the change I believe to better insure their copyrights remained recognizable.
- A G2 pony's copyright date will be between 1997 and 2003. You can see the bottoms of Satin Splash's feet have indents to protect her markings and a new addition. Stamped under her top right hoof is a rainbow, Hasbro intended their second pony line to be much more unmistakably My Little Pony brand than their previous line.
- A G3 pony's copyright date will be between 2002(??) and 2007(??). You can see the bottoms of Sparkleworks's feet have the tiniest of indents to protect her markings plus a very obvious new addition. Embedded in her her top right hoof is the G3 My Little Pony logo, made of light pink plastic. The material is different than the material the rest of the pony is made of. The logo is the same color on every pony. This is the most intense branding the ponies have seen yet. You might have been able to file the copyright marks off the two previous generations, but there is nothing you can do to unmark these ponies short of prying the logo out of these ponies' feet (which would be a little obvious).
- A G4 pony's copyright will be between 2010 and the present. Again, the current My Little Pony logo is stamped on her top right hoof, with the copyright date on the bottom left. The bottom right hoof is stamped with the country of manufacture, in Twilight Sparkle's case (below) this is China.
- See also Hoof Markings