Reginold 101 questions. First time owner . Any info would help!!

Hello all . This is my first time posting here and I'm looking forward to maybe getting some help. I own a small "Reginold 101" . I'm looking for the piece pictured below. If anyone could tell me wherei could order one please let me know.

That looks like a flue collar. What's wrong with it? Here's an ad for your stove from 1977.
https://news.google.com/newspapers?nid=2194&dat=19771205&id=4qIyAAAAIBAJ&sjid=D-4FAAAAIBAJ&pg=3263,2622935&hl=en

May be tough to find one of those collars. Looks to be cast iron and that is tough to weld properly. I assume you have the piece in question, so... might consider having one made from steel by a competent welder. Looks as if it bolts on with those two ears. I am guessing there is a bit of stove gasketing material or cement to seal in to the stove under the ears and around the outer diameter? Good luck with it.