Here is a pic showing the anti-slip tape.
It is usually applied by the crew and there is no set pattern, I have seen it running the other direction (across the cabin) as well. As you said, not all aircraft have it either. I have also seen some with thick, black anti-slip sand paint similar to what is on AFVs.
For the ammo feed chutes, I contacted Cobra Company and bought just the 7.62mm ammo feed chutes out of their UH-1N Weapons Set. Chris is great about selling individual parts from his sets, just send him an email.
For the spent shell ejection coils, I used some pieces from an old Star Wars Speeder Bike model. They are coiled hoses from it. You can accomplish the same look by wrapping thread or fine wire around tubing or heavy wire that has been bent into shape.
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
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