As far as I know the only TRO that the Unseen Longbow featured in was the 1992, TRO3031 Hardware-Handbuch published by German-FanPro, which was a German printing of TRO3026 but with some of the soucebook mechs at the time, ie. Flea, Raven, Wolfhound, Cataphract, and Longbow.
But of course that is not canon and thus not an official TRO.
Basically the Longbow does not get an official TRO entry until the original TRO3058 and at that point the image was already given a make-over, which I actually prefer over the original unseen version.
I wouldn't mind seeing a miniture of the primitive Longbow from Primitives Vol. 3 O0