I have three antique JFET buffers from National. LH0033, in metal can, gold plated, 12 pin, laser trimmed.
http://www.national.com/pf/LH/LH0033.html
Check my homepage for details, the "for sale" section.
http://www.national.com/pf/LH/LH0033.html
Check my homepage for details, the "for sale" section.