With the age of the plastic you will break more than you want. I'd suggest that you go ahead and order a full set just in case because I broke more than I want to admit when I took some off a few years ago.
Yes of course, new clips will be ordered.
What i do not want to damage, is the metal trim, the frame. I'm not sure, if that is the correct word for that...
Metallrahmen or Zierrahmen we would say ;-)
There is a tool for removing them. It slides between glass and molding. Slide it till you feel it catch the clip then slightly pull the tool forward, this should release the clip from the molding.