The "standard" mirror arms (non-telescoping, non-straight arm) for 47-55 were:
47-50 driver's side (left side) stock/standard equipment mirror arm (for doors with no vent window) 51-55 driver's side (left side) stock standard equipment mirror arm (for doors with vent window) 47-55 passenger side (right side) optional/accessory mirror arm I do not think that a chrome arm was GM-available from 47-55 (but, use them, if you like them).
I think that there are also no chrome/stainless round mirrors from GM in 47-55.
I use reproduction round black mirrors that are stainless steel under the paint.
I also like convex mirrors on both sides.
And, I like a 6" round mirror rather than the original 5" round mirror.
Do whatever suits your truck/tastes.
