Is my Apple Watch series 2 waterproof?

See the following from Apple Watch Series 2 - Technical Specifications

Apple Watch Series 2 has a water resistance rating of 50 meters under ISO standard 22810:2010. This means that it may be used for shallow-water activities like swimming in a pool or ocean. It is also safe to wear it while showering or in a hot tub. However, Apple Watch Series 2 should not be used for scuba diving, waterskiing, or other activities involving high-velocity water or submersion below shallow depth.

No. Actually there is no Apple Watch which is waterproof. They are water resistant, but that can and usually does change over time and use.

Read this --> About Apple Watch water resistance - Apple Support

Since Apple Watch is only water resistant and Apple Warranty does not cover damage caused by water intrusion, I would be extremely careful getting my watch wet.