Simple answer, yes.
If you have a large piece it can get very hot when setting, which might cause some issues with the mould. I've only used Pinkysil, which is an addition cure silicone, so it should have decent heat resistance.
You can also slush it around/turn it as it is setting to get a hollow casting, with less heat produced, if the mould doesn't have too large an opening.
Hope this helps.