I'm seeing maybe interesting things searching for info on this. The
LA Times article here in 2010 says the customer service reported 10mg zinc per Zincam Rapidmelt. But it said zinc gluconicum was the only active ingredient. The box I bought a week ago had that (1x) and zincum aceticum (2x) and Echinacea as active ingredients. So, likely different.
Zinc gluconicum is indicated as equivalent to zinc gluconate at Wikipedia.
One question at Amazon for Zicam asked about zinc content, eliciting this response from an apparent customer:
13.3 mg. You can get more zinc from a daily supplement, depending on what your needs are. you would have to take 6 Zicam to get 80 mg. It would also be cheaper to just buy a supplement.
Of course, I cannot vouch for that! If it's true, it would be roughly the same as Cold-Eeze zinc lozenges.
Sambucol's FAQ sheds no light that I can see on the zinc content of their products.