Chosen Solution

After replacing a battery in a Surface Pro 4, I discovered that the right-side speaker cover was missing. (I accidently removed it when cleaning up the old adhesive.) At this point, I’m not planning on removing the LCD to replace it but would like to have it on hand if I need to do so in the future. Here is a picture of the existing cover on the left-side speaker:

and the right-side speaker missing its cover:

I had the same problem after removing screen, accidentally removed the speaker covers due to overzealous removal of adhesive. They are basically just “stickers” that cover the speaker holes. I dont know if you can buy those though - I looked around and was not able to find anything. However, I had purchased a broken SP4 just for the screws and EMI shields. I was able to gently heat the speaker “covers” and put them in place on the SP4 I changed the screen on.