The story I'm about to tell you started a long time ago, when I was a Zilla rookie. I saw several part numbers on the 87 (which I new was the first year of Zilla) fiche that looked funny. It started with the clutch basket. The fiche said it's number was 21200-43B01, and that it didn't supersede from an earlier number. I thought it was strange. Fast forward to a few months ago. A friend at a dealer gave me a book with ALL the Suzuki parts ever imported to the United States. I call it my spellbook. This spellbook, when used properly, can be used for finding interesting parts, and it told me my intuition was correct about the clutch basket, so I started looking at more parts. These are the ones I found to be the non original parts. Who's to say if these parts were ever in the hands of the public?

These are 87 Zilla specific parts.

The CLUTCH BASKET was originally 21200-43B00.
The PISTON was originally 12110-43B01.
The PISTON was originally 12110-43B01-025.
The PISTON was originally 12110-43B01-050.
The CYLINDER HEAD GASKET was originally 11141-43B00.
The 2 FRONT BRAKE HOSES were originally 59240-43B00.
The FRONT FENDER was originally 53111-43B00-25Y.
The RH DISK COVER was originally 59230-43B00.
The LH DISK COVER was originally 59430-43B00.
The HANDLEBAR was originally 56110-43B00-291.
The REAR MASTER CYLINDER was originally 69600-43B00.
The SWINGARM was originally 61000-43B00.
The RESERVIOR BRACKET was originally 62420-43B00.
The 5TH DRIVE GEAR was originally 24251-43B00.

These are non 87 Zilla specific parts.

The 2 GRIPS were originally 57211-19A00.
The 8 DRIVE PLATES were originally 21441-07A00.
The 2 DUST SEALS were originally 62624-01B00.
The ACTUATOR STATOR was originally 12682-00B01.
The WARNING LABEL was originally 68366-22A00.
The 2 FRONT HUBS were originally 54111-19A00.
The FUEL TANK CAP was originally 44200-19A00.
The HEADLIGHT BRACKET was originally 51530-19A00.
The KICK STARTER was originally 26231-22A00.
The CLUTCH AND PARKING LEVER ASSY was originally 57800-19A00.
The PICKUP COIL was originally 32150-19A00.
The PARKING BRAKE SET was originally 69230-19A00.
The SPROCKET GUARD BUFFER was originally 61396-19A00.
The SWINGARM CHAIN PLATE was originally 61421-01C00.
The STEERING STEM SEAL was originally 51662-19A00.

I'll probably do the other years too.

Since most of the parts are 87, first year, it was probably very early production parts that failed/didn't work and were quickly swapped for current part #'s. Typically recall/defective parts and there #'s vanish from oem parts lists. Kinda like the big names sweeping failure under the rug if you know what I mean. Kinda interesting that many screwed up #'s though.

As for grips and fenders could just be a material or style revision. As for the cylinder possibly a big reed for 88+ bikes or possibly a factory duner option, hard to say its all speculation.

If you look at the picture, in the upper right, you'll see that it's drawn as a big reed.

???
I see a 6 bolt reed.

I see 7 bolt holes look at the top of jug lol and 8 peddle reeds the best of both worlds