Yep, there is a hollow-fist rubsign Soundwave (I have one myself, just looking through my box of Soundwaves). I'll create that record ASAP, but I am going to hold off on filling it in for now.
At the time of creating the records, we weren't super concerned with stampings (and even now, it's sorta "back-burner" as I can only imagine the public outcry if we listed every stamping variant that every Transformer could have possibly had over the years). A Seaspray is a Seaspray is a Seaspray no matter if it was made in Macau or Japan, unless it had some major mold change from one country of production to the other. But, getting back, as far as the Soundwaves and his battery covers go, courtesy of Fred's Variations Page:
Type 1: Takara-only (inside), solid fists
Type 1a: Takara-only (on battery cover), solid fists
Type 2: Takara-only with dates(inside), hollow fists
Type 3: Hasbro-Tak with dates(inside), hollow fists
So...yours would likely be a Type 2...but, as I understand it, that doesn't necessarily mean it will have a cover with stamping on it. It's possible that it might, but it also might come with a blank cover. You could have a hollow-fist, rubsign Soundwave with stamping on HIM and HIS DOOR or a hollow-fist, rubsign Soundwave with stamping only on HIM and nothing on his door.
Looking at my Soundwaves, I just ran across a blank cover, but it's different than the standard blank cover. This one actually has a squarish area that looks to be "blocked out". Neat.
So, as you can see, lots of "fun" can be had trying to put Soundwave's variants together.
Give me a bit more time to research it and maybe I'll come up with more info. I do agree that the stamped vs. non-stamped battery cover piece should probably warrant a new part record...
And of course, variants as a whole are a "work in process". To me, the more accurate we are, the better the site is, so I'm all for finding "new" legit variants.
MIKE
engledogg