From what I have read, the 7.0 board had an error in the silk screen. The 7.0 board series was one of those early models that Commodore messed up with the pin outs on the ROM sockets. They fixed this with what was known as a "Rom Tower".
So, in essence, the Rom Tower appears to be a hack to re-direct the pinout of the socket to the correct motherboard pins.
There is no mention of the pin to pin corrections.
