J-Type OD question

[DUHART JOHN <duhart@symbol.com>]

Hey All,

        Well I looked at a parts car (TR6) this weekend.  The car was in boxes 
and the guy was quite confused as to what it was worth ($1,000-$1,500).

        However he did have a J-Type OD, but as I had it in my hands I realized 
I hand no idea how to tell if it use of and use.  I turn the rear (the 
piece that connect to the prop-shaft) and it was locked!  Is this 
correct.  What do I look for to tell if a OD is worth making an offer on.

Thanks,
JHD IV