This is the SD13 Shirou Tachibana body. The difference in this body versus any other standard SD13 boy body from the same point in time is only the hands; at the time they were apparently exclusive. The same sculpt is now available as an optional hands set. Just to give you some idea about the changes of the bodies over time I'll talk about the Tokyo Boys specifically -

Shirou Tachibana - standard legs, old resin, old knees

Tsukasa Konoe - standard legs, old resin, new knees (knees have different sculpt)

Isao Nanjou - long leg (long SHIN - apparently Tohya/Kohya has long shin AND thigh), new resin, new knees

I intend to try to do some good comparisons of the Shirou body versus the Isao body, but these pictures will be specifically related to any differences you'll encounter in stringing.

Here is the difference in the attachment system for the foot. Whereas the new body has a jump ring (metal ring) embedded in the resin, Shirou's foot has a "loop" made of resin. The opening into which the s-hook is inserted is, therefore, smaller. Volks calls the new system "one-touch"; it is somewhat difficult to maneuver the s-hook through this hole in the resin. I'll also note that there is probably no difference in solidity over time of either design - the resin loop, while quite thick, is not cast in the same piece as the foot but is attached separately.

The foot has the same "locking" design as on the newer bodies; a tab on the ankle ball slots into the back of the foot (you can see it just behind the loop).

Basically the same setup in the hand as well, but the attachment is a hook instead of a loop. On the Isao body, there is an embedded jump ring. It's a little harder to keep the s-hook from sliding off the resin hook while re-attaching the hand than it is with the jump ring, but the difference is pretty minor.

This is NOT the oldest type of Volks body; in those, the hands were attached to the elastic via a length of string.