I would think it's unlikely there is anything remaining to hurt the finish or function of you G27.
One of the fun parts about getting a new gun, and especially if it is used, is breaking it down and going through it and giving it a good cleaning. I would break down the slide also and if that is something you haven't done yet go to UTube.
I use a lot of alcohol to do my initial cleaning and scrubbing and that should get rid of any bad stuff on your shooter. Lube lightly and away ya go.