I just re enlisted in the Army from the Marines my paperwork says E4 am I a specialist or a corporal?

Great question, Congratulations Cpl Garrett Camacho the Army looks at E4 in a different light. The most likely senario you will be a SPC unless your unit is in need of an NCO and they will make that determination.

Cpl Garrett Camacho unless they slot you in an NCO billet on the MTOE or TDA and the BN CDR signs off on it, you are a Specialist. They will not do that sight unseen as they officially surrender getting a Sergeant E5 until you are promoted or you vacate the billet.

You are a Specialist until you are assigned a leadership position due to availability of ranking leadership.