Finally I found where the inspiration for the nose cone had come to Kawamori-San.
Pentech M-80 Ten color pen!
Ten-Color Pens by Pentech:
It's called Fireworks and is more oriented for children. It writes pink, green, red, yellow, blue, black, aquamarine, purple, orange and brown. Each ballpoint cartridge is retractable. There are ten push tabs of the corresponding color. Sliding one tab all the way forward will lock it in place. Pressing the plunger releases it and another color can be selected. Length is 5" and is 23/32" in diameter. It weighs 19 grams, or a little over 5/8 of an ounce. This is model M-80. The address is Pentech International Inc., Edison, NJ 08817 (China). It sells at Wal-Mart for $1.94.
In our lovely SV-51:
Just nose cone and spikes around it which are part of the active stealth system