RV800 What exactly have you got on your licence? you cannot have AFI privileges and be a FI (Unrestrictd)
Presumably you were issued with, or renewed an AFI rating in Dec 99. Have you upgraded it with 100 hours Instruction plus 25 supervised solo sorties? if you have, then you have a FI rating, if not it could be either AFI or FI(R)
All ratings issued prior to 1 Jan 2000 are on the old 2 year system (25 months) so you must revalidate before the expiry date by two out of the three requirements. If you let it go past the expiry date you will have to do a Test and attend a Seminar to Renew. If you have got the hours, do a test ASAP, it will be revalidated from the expiry date so you don't lose anything.