Well if I'm right the speaker grill is just glued on. Does that make it easy? Not exactly. You have to heat the glue enough to pull it off but not to much that you overheat the internals of your phone. Then you have to try and wedge something in between the grill and the other part of the phone without damaging it.
Can you do it? Of course. Is it easy? Not really sure
This is the glue/tape i use when i replaced several screens on phones in the past. I cant say for sure that it would be compatible seeing as i've never opened my One
2Mm 3M Adhesive Sticker Tape LCD Screen/ Digitizer Sticker
Try the second one i posted. Or copy the first one and paste it in your search engineI cant open the link...is there something wrong with my pc?