you can change it, you need the whole grille. I dont know if the market has different qualities, but best quality should be oem one. Honda I would think sell them separately, or check for genuine used ones.
Double sided tape would hold the moldings, could be taken off with care. Use a heat gun (not too hot), then peel it off. Then after you have to deal with the tape residue, a bit of wd-40 can help.