Depends on how you want to use that information, and what purpose it will serve.
If you produce such concentrate, you can be looking for buyers, or assess the profitability of your operation. Depending on how accurate you want to present the cons or assess the viability of the mine/plant, you can seek professional lab which will perform fire assay or some sort of ICP and other stuff to precisely measure the content of high and low value metals. Here you are in the right place to ask very experienced guys - who can help you decide what test best suit your needs, as they have more than century of combined experience in this area.
If you indeed want to sell the cons to the bigger buyer, you would need to claim what you have - and thus pro results will come in handy - serving as good proof of what you have.
On the other hand, if you just need some approximate numbers regarding your cons and also setup used for the recovery of metals, other thing you can do is process a larger sample by a viable method (like smelting the cons in induction furnance+graphite crucible to reduce everything from noble metals down to iron into one metallic puddle), which will give you pretty good numbers on how much of what metal you have in the cons. It also tells you what you can recover with your methods - and thus what is real "yield" from the ore/placer you have. Zinc won´t be captured by this procedure well. Best is to have process sample combined with also pro lab results to compare these two - and assess the losses on particular elements. But metallic product you obtain can be analyzed with good quality XRF to give you quite usable and reliable numbers. And this is cheaper than sending samples for pro ICP + fire assay.
However, I need to say, if you do not have experience with advanced smelting techniques and lack proper equipment, I would strongly advise going with pro labs. Yeah, it can cost quite a bit of money, but you will have certified results, on which you can further build your setup/operation/calculations, or negotiate with potential buyer from stronger, more credible position.