I still have an A1000 built in October-November 1985, and yes it was the Amiga 1000 model number A1000.. The A500 and A2000 replaced the A1000 and was launched within a month or so of each other. The A500 and A2000 was a cost reduced all in one keyboard unit that incorporated revised custom chips while adding things like more CHIP_MEM (memory addressed by the custom chipset). People back then didn't look at the model number because there was only one Amiga at the time so to many people it was just "the Amiga".. No one had a clue that Commodore was reshaping their line into one that worked more like the 64 and a version with more high end slots for business apps and better "IBM" hardware compatibility..
Hope that helps get you out of Amiga "Fireworks" mode about all of this.. The A500 was a response to the Atari ST and the later to the Apple ][GS..
