No. Baptists hold that the Lord's Supper is a church ordinance, to be observed as a memorial of the death of Christ. The bread represents His crucified body and the wine represents His blood shed on Calvary.
In Lutheran belief, consubstantiation is a doctrine saying that the substance of the bread and wine coexists with the body and blood of Christ in the Eucharist.
Catholics call it transubstantiation but Baptists call the rite a "reminder" of Christ's sacrifice.
You become a Southern Baptist by uniting with a Southern Baptist church, one in friendly cooperation with the general Southern Baptist enterprise of reaching the world for Christ. Typically church membership is a matter of receiving Jesus as your Savior and Lord and experiencing believer's baptism by immersion.
See Southern Baptist's basic beliefs on SBC.net.
For more info, read this article: The Lord's Supper: who should partake? - encompassing four reflections on the Lord's Supper adapted from SBC LIFE, the journal of the Southern Baptist Convention's Executive Committee.