Yours is a 17! I have the exact same pistol as yours but an earlier model (i believe). My grips say UNIQUE close to the top and there is a lion near the bottom.
Remember they made a whole lot of these pistols and they were made by many different companies. Mine is clean of markings other then the same as your slide and the serial number.
Sadly there are no Nazi markings on mine. As to the barrel turning and coming out that is a correct way to take it down.
Resident of the Northern Republic of California
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote" - Ben Franklin