Ok... I've had time to cruise online for some donors and "fixers" for sale, mostly on Ebay, and it seems that there's a TON of confusion regarding the identification of different SX70 models... specifically the tan/chrome models. I'll do my best to bust some myths (I've touched on this before but just a bit) and clarify some differences between SX70 Model 1 and SX70 Alpha 1.
There are some exceptions though. I've seen some "transition" models that have both brushed and matte parts. Most often though, if the faceplate is matte, its an Alpha 1. It's impossible to replace a Model 1 brushed "chrome" faceplate on an Alpha 1 without modification.
How to identify an Alpha 1:
Flash fill capability - While not a visual cue, starting with the Alpha 1 ECM substrate (circuit board) users had the ability to use flash fill in daylight shadow conditions. This was automatically determined by the camera once an electronic flash or flashbar was connected to the flash fire assembly. From what I've researched, all cameras have this capability with the exception of early Model 1 and some Model 2 cameras.
Focus lens scale - Early Model 1s simply had tic lines on the ring of the lens while Alpha 1s have distance increments. This isn't entirely reliable as some older Model 1s were retrofitted with numeric lens rings.
In a nutshell... Alpha 1s are awesome. Heck, all SX70s are fantastic! Just keep your eyes open before buying what some folks may call an Alpha 1. They're most likely not trying to rip you off but it will help knowing what to look for before you pull the trigger on a purchase. And of course if it doesn't work I'll be happy to fix it for you (shameless plug). Shop's closed!