My advice is to leave it. SHould anyone wanna buy, they'd rather have it in original condition. Still, up to you. And it won't be cheap to sand and spray as you request.
F78xxxx (what i predict it should look like) means that your guitar was made in Fujigen in '87. If the number of digits are wrong (more or less than 7) please inform me. If not, the above information is likely to be correct, As for the model, who knows? Ibanez website doesn't have the serial number thingy.