* * *What an odd problem. Ive just had a look at mine (panic) and while there is no rust, I did notice the iron frame is powder coated (at least on the outside) so I wouldnt recommend sanding it back and painting. You may be able to use a rust converter and then touch up with a paint stick.
Do you have a Silvia with rust or are you asking Do they rust?"
If yours is rusty, how did it get rusty, is it coming in to contact with water in a place you cant see / get too? Which may indicate a leak is the root cause ?
How old is this Silvia and how bad is the rust? I reckon if mine caught the rust bug, being made out of stainless and powder coated steel, it would take a few decades to invalidate its functionality. ;D