Such an error of 500 hours instead of 5000 hours would be very obvious when viewing it together with types flown, length of time flying, places flown, previous employers etc. It would all come out at the interview, long before the letter of offer.
Falsifying a logbook is cause for instant dismissal and then the 'word' gets around the industry, not to mention the interest of the aviation authority that issued the licence and that may lead to prosecution and the removal of a licence.