Paragraph «Universal Cenruty» says that tail binders are «First equipped on MSN-00100 Hyaku Shiki», wich was 1st seen in 0087 U.C. But, if you watched Stardust Memory, you could notice in 11'th episode that tail binders were already installed on RX-78GP03S Gundam «Dendrobium Stamen» in the end of 0083 U.C.
These mistake should be fixed, but I can't do these by myself 'cause, as you can see, English isn't my native language.
They certainly resemble binders, but the defining aspect of a binder is that it functions as an extra limb for AMBAC purposes. The question is, do those objects actually have an AMBAC function, or are they solely used as attachment points for docking with the Dendrobium Orchis?
There are a couple of pictures where the boosters on the hip/leg area are called "Tail Binders." However, the Hyaku Shiki is stated to be the first suit to use Wing Binders. I'm not sure what the difference is, but I would assume that binders on the Stamen can't really be used as an additional limb and were not intended for AMBAC, and really only serve to hold and protect the thruster and docking interface for the Orchis. The Hyaku Shiki's binders were added with the entire purpose of acting as another limb to aid AMBAC in mobile armor mode, and were found to still be useful when the mobile armor mode could not be realized.