Those pieces are from 9495. There's a fine greyish line for the sides of the cockpit, but I don't think it warrants putting an entire grey slope for it, making it half white and half grey. Also, if you compare with 9495, the grey pieces are at the bottom, while 75172 has it at the top.
Got the latest Y-wing recently, but didn't really like the Sand Blue, so I thought I'd modify mine using parts from 9495 and change the color to light bluish gray.
Here's how it looks overall.
But I got a little troubled with the stickers on the nacelles, so I thought I'd copy the build from 7658.
I used all the parts as suggested except for the toolbox wrench which I skipped since it was used for greebling purposes. There are places where you can substitute for color, but I chose to stay on target
Thanks! Took me a while due to delayed postal services. I didn't replace any of the hinges, found a BrickLink store in the UK having tonnes of it, so made a large order from him with the rest of the parts that I needed.
I did omit some of the more rare pieces like the Tool Box Wrench in Dark Bluey: https://www.bricklink.com/catalogItem.asp?P=6246d
Picked up about 60% of the parts from a used bulk lot that I had no time to sort, then 1 order from my own BrickLink store (am too lazy to go about reducing the piece counts from 33 different lots) and another 3 more orders from other sellers and I'm all set to build this!
Now if only the other BrickLink stores can ship their parts to me like how I shipped mine to myself
This is superb. I'm looking forward to gathering the pieces for this and am wondering if those hinge with 2/3 fingers pieces can be replaced with alternate pieces?