I've heard his legs are not the same, but I'll wait for the ILM model, if we do get on on the Blu ray. The other image is from Josh Nizzi, so I'm not sure it was complete at the time.
Soundwave's gone through countless changes during the trilogy. When his concept was first revealed for ROTF, he was to transform into a black Chevy Silverado. A few design changes have been done to his head. The most ridiculous being a small box with beady eyes. Then when he was revealed in the comics, he had several spikes or whatever all over his body. He was just a silhouette but you could tell he was clearly gonna look different. Then we get his robot mode for the satellite mode. Pretty much stayed the same until he got to Earth and transformed into the Mercedes. Now he looks a lot different again. And, to top it off, his HA figure has tiny legs (I'm still buying it over the deluxe), and the deluxe figure's legs look totally different. Long story short: ROBOT DESIGNERS, Y U NO MAKE UP YOUR MIND?