Does anyone know if HF 416 sights are available to the public??  If so, where?

They ARE available.  

There is/was a guy on Sturmgewehr.com selling them for about $300 a set.

Check in the ar15 forum there is a guy who is about to machine some. his thread is named, "Would anyone be interested in these if I made them" or something like that. It as about 10 pages of replies and is usually at the top of the ar15 forum or on the second page. Hope that helps.
-jls7

Edit: I just looked on the ar15 forum and cant find the thread that I mentioned, it might have gone down past page five... post this question in there and someone will reference you to the correct thread.

Be advised that you will need specific front sights for this particular rear sight aperture.

Quoted: Be advised that you will need specific front sights for this particular rear sight aperture.

Best bet is to get a set from HK to avoid problems.  I think the sights are 3/8" shorter than standard AR sights because the rails on the 416 are 3/8" higher to fit the piston works...  So, used on a 416 everything is normal-normal.  Used on a standard AR these sights are a bit short and require you to move your head...  

I'd like to see the other guy's sights in person before being completely convinced.  I know that anything with HK on it from HK themselves will be top notch, no questions asked - this guy is an unknown quantity at this time...

Spooky

Here is that thread re: HK style sights