Is it real or a knock off?

I own a Walther PPK/S .380 acp. and I'm always looking for spare mags to use at the range. Last week on another forum in the Accessories for sale forum I found a magazine, brand new,, for $25. I asked a few questions to clarify the caliber and the pinky rest. I sent the money and got the magazine but was disappointed with the item. This magazine was brushed steel on the outside and the pinky rest was shiny black hard plastic. All my other mags are nickel plated and the pinky rest is a dull black plastic and are a different design. I should mention that the seller offered a full refund but I declined because it was exactly what he described in his ad.
I think that the one I just bought is either an earlier design by Walther or it's one of those knock offs from Japan.
My problem is that if it is a knock off I would never use it due to safety concerns.
Anyone have any suggestions?

If you're not confident in using it for carry, don't fret. Use it as a range magazine. If it causes some malfunctions, so be it, you'll get some immediate action drills for the price you paid. That's worth some value right there.

I would only use it at the range.

Case closed---she's a "range only" mag.