The halftrack is sold as a separate kit(biggish item), both the halftrack and the 88mm gun get re-issued at times.
I can't remember if the kit included the Motorbike too(don't think so), I got mine with a few extras when I build it (Kuebelwagen, Halftrack and a 1/48 storch to suspend over the Dio)
I did a 1/35 scale version of the old Hasegawa 1/72 Diorama of said piece.
Either way it is a fairly nice kit considering it's age.
[edit]
Just checked with Hobby Link Japan the kit INCLUDES 1 laison rider with
Zuendapp KS 750. Sells on HLJ for $20.
Here is a link to the halftrack:
http://www.hlj.com/scripts/hljpage.cgi?TAM35148
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