"I saw" is not correct, if you did not see. Likewise, "I have seen" is not correct if you did not see. :D
Furthermore, it is grammatically incorrect to begin with a conjunction, such as the word "but." :eek:
Still furthermore, it is grammatically incorrect to separate two words or two phrases with a comma when they are separated by the conjunction "or," as in "'I saw,' or 'I have seen.'" :p
Worse still is correcting the moderator of a forum. :(