rear left turn signal hangs by wire! need new part...

Hi all, my bike's rear left indicator light is hanging by the wire. The hard plastic part is broken around where the bolt clamps it in place. if you click 1986 Honda VF500F OEM Parts, 1986 Honda VF500F OEM Motorcycle Parts - BikeBandit.com, I'm looking at part #10, as shown in the diagram, which is the broken part in question.

1) in the parts list, what does the *NH1* mean?

2) Are the rear turn signals the same as the front signals, except for the length of the stays (parts 14 & 15)?

3) should I splurge and just get part #12 (the entire turn signal), or is this simple enough to just replace the housing (part #10) and save $20?!

Thanks very much