It's not a .2 series. The layout of the ends were different on the .2 series. The .2 series didn't have a DIN-style input, and the RCA's were horizontal not vertical on the .2 series.
And I agree...it looks too small to be an A300. There is one on ebay right now, and the A300 on ebay looks wider than this amp. The graphics are much more spaced apart aswell, showing the obvious width differences. I'd say A100 or A200.