Your FH36B was built in 1993, and the Allegro is from 2003.
One way to tackle the worn-away spots in the lacquer is to take your harp to a woodworker who has experience repairing and spraying nitrocellulose lacquer. If you're comfortable tackling it on your own, you'd probably want to start by wiping the discolored areas with a cloth dampened with Citrasolv or some other mild cleaner. This will help to remove any residue from skin oils or lotions that could gum up the works. Then, you'd carefully sand the wood with fine-grit sandpaper (maybe 320 grit) to get rid of the surface discoloration and to smooth the edges of the surrounding lacquered areas. Wipe or blow off any dust and make sure the surface is really dry, and then you can use an aerosol can of lacquer to spray over the top. We've used a product by Konig called KO339, which is pretty easy to use (although it may have additives that make it behave a little bit differently than the lacquer we use in our spray booth here).
Regarding the brass plate, you could take it off and polish it with some fine steel wool. You could even take it to a trophy engraving place and have your harp's name put on it! Just know that it will likely tarnish again unless you coat it with some kind of clear fixative or lacquer. And before taking it off, be sure to down-tune the harp by a fourth or so to take some of the tension off, since the brass plate is a structural element holding the neck and pillar together.
Hope this helps!