There are lead testing swabs on amazon.com all metal devices should be swabbed to test for lead especially the cheap Chinese ones
Have you heard of lead being found in a device? It would surprise me given how soft it is. It wouldn't be good having it close to the skin if it was present.
You should be testing for Nickel, it's unlikely that any body would use lead. Nickel test swabs are also available. In the UK it is now illegal to sell any item of jewellery or clothing that contains nickel plated parts as it can have a nasty allergic reaction on skin.
Some devices used to be made from chrome-plated pewter which may contain a small amount of lead. 316 stainless contains 10 - 14% nickel so care is needed in interpreting any test for nickel as you might just be rejecting a very safe material.