New Lining Bottom Plate Okay?

[Mac227]

Hello all! We recently had a stainless steel liner put in our chimney but we haven't used it yet. When I look up at the bottom plate from the smokebox, two of the sides seem flush with the walls but the other two (circled in pic) don't appear to be. I'm worried if there is an opening that some debris / smoke could get in. Is this an issue? We only have an opening for where the opening of the damper was attached to the smoke shelf, so not sure how to even get up there if it needed to be worked on.

Thanks for your help! I'm a novice in this area so would rather be safe.