Are electroless nickle plated slides, 1990 vintage, on German P220's unusual or rare?
Someone please educate me.
Thanks.

No they are unusual or rare, IMO.

There were certainly fewer nickel guns than blue/blk.

At that time, I believe Klein Plating in Erie, PA was plating the Sigs.

In 1992, I bought my first P-220. I called Sig and asked if I could send it to them to be plated. The referred me to Klein, who plated the whole gun, and 2 mags for $100.00.

We often see ads on GB that tout early nickel Sigs as rare. Many times they do not even have the proper markings on the box to indicate they are actual factory (Klein) finished.

This is my opinion and I believe others will back me up on this.

I have several of the "Factory Nickel" Klein plated sigs, both full and two-tone. They are beautiful guns. I believe these were guns imported from Germany as black and sent by SigArms to Klein for plating after they arrived in the US.

The ones Sig had plated will have a notation stamped on the labeling of the original box.

I'd say they (the "Factory" ones - not the "copycats") are unusual but not really that rare. The real ones should command a higher price than a plain version but not exorbitant.