A final note and information on this topic. I received the new plungers from Forest River. Problem is, they have mounting brackets with 3 inch on center mounting holes. The plungers on my coach have 2 inch on center mounting holes. Apparently, the 2 inch are no longer available. The best way to try and use these new plungers, is to drill two new holes in the mounting bracket so the holes are 2 inch on center. That certainly is easier than trying to drill new holes in the door frame, especially when you are working on the lower latches which are covered by the curved door skin. Hopefully this will work. The challenge is still getting the old plunger out, and the new one in without damaging the curves door skin.
Also, I contacted RB Machining/RV Division, motorhomelatches.com and they tell me that the latches for Winnebago are the best match for our Tri-Mark latches. They come with four holes in the mounting bracket, both 2 inch and 3 inch. However, they do not come with new cables. You must reuse your old cable, or find a replacement on your own. Price is $16 each for the aluminum plunger.
Hope this helps anyone else faced with replacement issues.
2012 Berkshire 360-FWS
2003 Jeep Liberty Dinghy