The fitting is steel. It does conduct electricity. Just for the record, so does aluminum. In fact, aluminum is a better conductor than steel.
Silver is the best conductor and therefore is rated as a "100", aluminum (Al) has a conductivity rating of 63, copper (Cu) is 97.61, gold (Au) is 76.61, carbon steel is 12. The higher the rating, the better of a conductor the metal is.
All this info came from the Machinery's Handbook, 23rd edition, p. 398.
This info also makes you wonder why electrical connections are "gold plated". Well, I guess that's better than steel.
Anyway, back to the fitting. These are steel because they are industrial hydraulic fittings and they are rated to above 3000 psi. You should be able to find a local Parker dealer in almost any town.
A book sale at the library? Why even bother? Why would I want to buy a book, when I didn't want it for free?