Thanks to YellowCorvette, we got to see some nice out of package photos of Bluestreak, coming exclusively to Walmarts in the US as part of a 35th Anniversary subline of Siege. This was apparently purchased from a hobby store in Malaysia, and isn't expected to have a release in the US until October.
We've got closeups on the new shoulder cannon accessories, including their combined handheld blaster mode, and equipped to both the robot and vehicle. Some side by side comparisons are offered as well, though none with Siege Prowl. Based on the photos, it looks like apart from the different accessory loadout, Bluestreak doesn't feature any physical changes compared to Prowl, lacking even a variation of facial expression like the seekers have.