Hi Janez, great information.
To be honest, i have a strange Apple II Europlus at home right now, The PSU has stickers to cover up the 110 volt label, the Logic Board is brown/green and a "Spike" name is present in the back side of the board (that code name is related to another Apple product, the Quadra 700)
The case label is not related with the Europlus (should be "IA2S2xx" and is indeed "A2S2xx")
Some modifications were done on the video side (i had no video before removing some)
the board and PSU seems to be original, both were dusty and a label E.M.A.C present in the bottom side of the PSU... was somehow also present on the base (like a transfer from the PSU)
Not saying is a prototype, just curious...