I've got a "Goldfinger" in .177 and an R-9 deluxe in .20. The latter has the same checkered stock that the Goldfingers have but has open metallic sights. Mechanically, they're the same thing.
The sights on my .20 might have well have been omitted from the factory or at Beeman. Doing so would have saved me the trouble of removing them. I have ZERO interest in using them.
Which happens to be a good thing, because the stock diminsions of the current R-9's sold here in the USA don't seem too conducive to the use of open sights. Neither I nor several other shooter I know could get their face down on the stock enough to get their eye lined up comfortably and correctly with the open sights.
With a scope, however, it is pure bliss.
Older R-9 models have more drop in the stock and are much more comfortable to shoot with open sights, IMHO.
-JP