There are several "Shockwaves" out there to this day because he was made by Hasbro and a company called Toyco. in Korea.
I can't remember if my Shockwave is from Hasbro or Toyco.? He has a rub sign so I'm assuming the he is Hasbro. I'll take a look tonight because I want to know now! My Galactic-Man is Toyco. I know that only because I just fixed him all up.
From what I know about Galactic-Man is that he was a Radio Shack exclusive in the early 80's. He's a dark grey color and his eye is red instead of gold. His trigger is noticeably differentI. Other than that he is identical to Shockwave. Honestly, I didn't know he existed until my wife's cousin said he had one!
Of course, I was jealous because I didn't have one and I LOVE "G1 Shockwaves" mold! I'd say about a year later he comes over and hands him over to me. I was shocked! He's a little beat up, his tube that attaches to his arm was all crummy and broken BUT the electronics and lights worked perfect!! Stickers were falling off and yellowed. He was used pretty good, and so he should have.
He's now in my hands and I ALWAYS make the best of my plastic crack! He now looks like this: