i don't think it's a combo, it could very well be pure ingame. Look at the sceenshot i've provide, there's no noticeable differences between them. And it was taken during the SH4 first look where neal or some other subsim.com fellows had been invited to take a look at a beta sh4. This is where that screenshot i provide was taken, to illustrate:
"After careful and deliberate calculations, I fired a couple of torpedoes. We switched to the outside camera to watch them speed to glory. I was all prepared to start bragging about my TDC skills when, as we watched them close on the target, Dan brought me up short by casually pointing out, "I noticed these are the training warheads on the torpedoes."
"It's a training warhead?" I sputtered, incredulous. "Yah, see the yellow warhead--"
So as you can see, this IS a real ingame screenshot and there's no noticeable difference.