To tag or not to tag?

[BeautyTheBeat]

I'm not sure which category this falls under, but I recently recorded a song for some local artists. My question is do I add in my signature tag or leave it out? They paid me to record them so I was thinking maybe I should leave it but If I leave the tag out how will anybody ever know who produced the song?

 

[SwagProductionz]

leave it in the intro and the outro of the song.... it's free promo so why not