you should post pictures showing this is a "jasper" chipset system, check the back power ratings for 12.1a on the rail..if so its a jasper system, which is suppose to totally defeat the RROD errors once and for all. Latest and greatest version of the 360. Google for more information....I own one and the system finally feels and sounds professional(i.e no flashy chrome, fan runs quiet as hell, power brick is even lighter than the old one since the system draws less power now)
During all the confusion of systems shitting out and rrod'ing microsoft went undercover in choosing new chips/components to run in place of the old faulty parts in hopes to fix the problem. They created a few new models with more efficient chips, mainly the GPU(less power consumption and less heat because of power ratings), but even the last few updates before the jasper chipset have shown to RROD. Jasper models came out on shelves in November of 08..guaranteed way to get one of these models is to snatch a Arcade bundle system(as the OP did). These machines also have 256mb built in flash memory, more than enough to save games.
Usually what Microsoft does is if the system has the classic GPU unit failure they just send you a brand new system... end of repairs haha. If you need to get rid of this and nobody is interested PM me and maybe we can work out something.