You should, of course, follow the advice of the owner who has actually seen your instrument.

If you'll pardon a little thread drift I'm still curious about the guitar. We may be stumbling over terminology. The tail block is part of the basic structure of a guitar and similar instruments; it's not a special piece installed just to support a strap button. Is the owner telling you that there is no tail block or that the tail block can't be used to hold a strap button (too little, too soft to hold a screw, too hard to accept a screw without cracking, etc)?

BTW it's pretty easy to look at the stuff inside a guitar. All you need is a flashlight and an inspection mirror - a little mirror on stick like the ones a dentist uses.
- Phil