Interesting question. The Primus 71, the Optimus 8R, 80, and 99, and the Svea 123/123R are all close cousins. Many parts are interchangeable depending on who made the stove when. The Optimus 199 is also in that family but is a little different. There are also some other manufacturers like Radius that made stoves in that class.

I have a 71L, it was my uncle's, and it was what propelled me into collecting stoves. The stove itself is a very good stove. The box/case is not quite so nice. It's a rather thin tinned steel and quite prone to rust. I think the Svea 123's brass windscreen is a much better deal. I also think the Svea 123's brass windscreen in combination with the aluminum cup make the Svea 123 more durable and more packable. I'm always a little afraid of bending up the 71L's case in my pack. On the other hand, IIRC, the 71's tank is bigger which can be of benefit on some trips.

In short: They're comparable stoves. They're both very good stoves. I prefer the 123. YMMV.

I don't think that you would hurt the antique value of the stove if you polished the brass, provided that you don't do something destructive like "polish" it with a wire wheel. Using citric acid, brasso, etc. should be fine. Anything that might degrade the engraving would definitely decrease the value of the stove.

Who will win the Academy Awards? I predict a movie will win Best Picture, an actor will win Best Actor, and a director will win Best Director. You heard it here first. lol

HJ