Remco fakies date back to the 80’s and appear in copied molds by other manufacturers to this day. The series of Pretty Pets consisted of “earth” ponies, unicorns, and donkeys; and a series of three pets. Real Remcos will have the company name and year stamped on the hooves. Some poses were re-made and will be dated 1982, 1984, or 1989 (as I have found so far). Note that the year categories below refer to the date stamped on the mold, and may not be the actual year each example was released.
Remcos are decent quality, except they have the accursed orange hair that tends to decay with age, so nowadays the rainbow hair ones are often lacking a stripe of color in the mane. Knockoffs of Remco ponies tend to be pretty low quality (thin plastic, nasty hair).
Click images to enlarge.
1984 Sea Pony
1982 Earth Pony (the original)
1984 Earth Pony (longer neck. This is the pose that shows up most often as bootlegs.)
This one is also marked 1984, but has a different shaped head, kind of cross between the pony and donkey:
1989 Earth Pony (much closer to the original; new style of eyes)
1989 Unicorn (mold looks pretty much the same; main difference I see is the paint on the hooves. 1984 paint is higher in the front and tapers in the back, with some variation. 1989 is more of an even line around. It is most noticeable on the raised hoof. The eyes weren’t updated like was done with the 1989 earth pony.)
1984 Donkey (same or similar body to 1984 earth pony)
1989 Donkey (same or similar body to 1989 unicorn/earth)
And this one… (this one is from my collection, but I put her in storage without collecting complete data on her, so I can’t report what her hooves say or if she’s even a real Remco)
1984 Baby (unicorn or earth pony)
1989 Baby (note different style hoof paint, same as adult style)
Pets (dog and cat shown; there was also a chipmunk)