I finally found my AR10'er book and even with all the info in it, there is only one reference to the H&H receiver that I can find. It is an ad for the receiver sold in June of 1984 in order to complete Portuguese kits. Dan's sales was selling the kits and the lowers were in a mated ad discounted to $275.00 from $325.00.
It is noted quite clearly the H&H would not ship without a signed copy of an FFL.
So, being semi auto only and having an FFL behind it, barring municipal, county or state assault type weapons bans/registrations - I'd say you're A-OK with an at least $2,000 rifle. Me, were I to part with my Portie - it'd be beyond the $3,000 I've already turned down.