It really depends. One thing is that the Wrist joints on the lamp are no good. You have to scratch-make them. When I get around to building another Crow, I'll buy a pair of metal Arms that I'm sure Bob still has. Shoot him an email.
In addition there's certain details of Crow and his arms that I prefer to have. Which requires parts from real desk lamps.
The first picture was taken during season 4, I based my Crow off of this picture.
I chose to include this triangular knob from the Desk lamps. (see picture 2)
You'll also have to cut the arms down to size, (be sure to have a Hacksaw with a new blade)
3 of the rods cut down to 9 3/4 inches. The final rod, (the outer rear one) is slightly longer. Roughly 10 inches.
You need the longer piece for the arms to fold up evenly.
Hopefully this helps.