Spoiler: maybe? Almost? His shooting% will likely dip (but maybe not very much) but his shot rate could easily increase if you compare him to the small handful of 18yr old rookies in recent times. Also, a bit of a surprise but his goals don't come from as far a distance as people tend to think. Much further than a guy like Stamkos though (who remains probably the best early-career comp to Laine).
I think the team just wants stability in net right now, which is what we get with this tandem. If we weren't going to extend Anderson, then the question becomes what other goalies are out there that will give the team equal or better goaltending and what is it going to cost?