Modding SRTT is kinda complicated. Let me explain you why:
1. We can't add new items (it's possible for SR4 only) so we can just replace other items
2. If you want to do that the file size of your modded item should be the same or smaller than the item you want to replace so that means less detailet model or/and lower quality textures
3. We have limited clothing slots options we can use so belly piercing like this you could make as face piercing or ear piercing because adding new slots is not possible
So my answer to your question is: Yes, it is possible.