Anthony the whitish material looks more transparent on the threads. I will try an download a picture but my cheap point & shoot which actually takes pretty good images just eats batteries, so it may be difficult getting an image to you quickly,
However I can try & describe it better. All it looks like is a T that comes off the left side directly off the central hub if you will of the regulator. The top part of the T there is a fitting that the CO2 tube is delivered to the solenoid. Looking just left of the T there is a small hex nut & then the dial itself for adjusting the flow.
Does the needle valve go in that part or does the whole T have to come out & be replaced as an assembly?? Once again looking right now you have adjusting knob then hex nut connecting to the T pointing up which goes to the solenoid, then extending with threads directly to the regulator, this is where I noticed some kind of solvent that is clear looking. Not tape.
Thats it: My guess is that small hex needs to come out to get at the needle valve & then replace with new one.
You asked about which needle I have & I cannot find manufacturer label anywhere on the regulator or needle valve. Looks like no name bran.