Prices for most of those in 9x18 Ultra vary from $500 to $1,000, depending on police surplus versus commercial, full package including test target and two magazines to a bare pistol, and obviously the condition. No import stamps are not common, but surprisingly not rare, especially on the .380 iteration (US military rod & gun club purchases). Based on those two photos, and assuming a single magazine and nothing else, it is roughly worth $650. Not sure why you mentioned the grips, but the OEM plastic are available on occasion for around $75-100, and Marschal Grips in Hungary makes wood grips that are well worth owning. OEM wood grips are relatively uncommon, and I have not seen them for sale separately, only as part of a gun for sale. The Supers are robust and reliable pistols, and make a worthy addition to an classic Walther collection, plus they are fun to shoot. Enjoy!
They are indeed Super. I shot a fellow forum member's Super (he got it from Geo IIRC) and I had one of my own a few days later.
I paid less than $500 for my RP surplus gun on GB but I got lucky and haven't seen one that low since. Geo has had more Supers than most of us here combined so I would always defer to his valuation. Don't pass on it if you get a decent price. Was a time when they didn't sell because ammo was VERY scarce. While there were not a lot of Supers made they weren't too hard to find. Ammo is no longer an issue so prices are going up and availability is going down..
I agree with Absalom, it is probably a surplussed police pistol. IMO, it is more likely to fetch $600 than $700 based on current sales. Here is a link to a nice commercial pistol wearing OEM wood grips that will probably sell for north of $850, and $1,000 would not shock me. https://www.gunbroker.com/item/862191653