FG-140 1971

The data on that serial number site is based on data I've shared in a table.  At the moment I have 2841 serial numbers, 463 with internal date codes.  Your guitar was probably finished late April/early May 1970.  If you were to find the internal date code it would be 45.4,??, which is when the sides were made.

If it is minty, it is certainly worth more.  How is the action??  Is that the original saddle height??  It's really low.

The FG-140 is the "budget" version of the very popular FG-180.  I think it's just as good, but it looks a little different.  It's a real sleeper!!

It depends on where you are trying to sell it.  Reverb & eBay might get $500, but locally may be $300.

That is interesting that the original saddle is so low.  It left no room for adjustment as the guitar got older and the action increased.  I've heard the action wasn't always great when they were new.  Maybe that's what happened with this one, the saddle was lowered in the first year.