It is also believed that 'Terada Musical Instrument Co., Ltd.
of Japan also made some guitars for Ibanez during this period.' It's thought that 'these would be mostly hollow-body guitars, but may also included some solid-body Artist series models.' There is no proof whatsoever for either of these assumptions.
Any production sequences above maybe 45000 may be assumed to be 1988 models, although this rule of thumb doesn't appear to always hold true.
In some cases a determination as to whether a guitar was actually produced as an 1987 or 1988 model can be inferred based on the finish (color) of the guitar, as some finishes are limited to certain years.
In cases where you have a serial number but not a country of origin, the origin can sometimes be deduced from the serial number, although in this case it's very helpful if you have at least a rough idea of the date of manufacture.
The false information this website generates has been propogated in numerous advertisements of sellers of vintage Ibanez guitars.It seems that Fuji Gen or Ibanez produced an overstock of these "F7" serial number stickers and so just continued to use them through 1988.