I'm surprised you haven't got an answer yet.
(EDIT #2: OK, after looking further at the 945 series, I'm going to change my answer completely. I thought there might be a chance, but now I can't say that. Sorry!)
Are you certain of the 945 mag capacity? I just looked up the 945 on another thread on the Forum that has a chart of the 945 variations, and the smallest capacity it lists is a 7-round. If that's actually what you have, then no, the CS magazines won't fit, sorry.
Catalog of Performance Center 945 Variants
There are a few 6rd 945 models listed on the link above.
945 Group 3 (Product Codes 170180 – 170227 (B))
I have a 170184 (B) No billboard model, and can confirm that it is a 6rd magazine. Unfortunately I don't have a CS45 to compare it to. But off the top of my head, I would say no, it will not work due to the different location of the mag catch slot. 945 mags are marked as such.
The CS 45 Mags will absolutely fit and work fine in it.
My guess is they made the 945 much later and designed it so it would also work in a CS45. I'm curious if it would also work in a 6 round 4513TSW.