Help Needed for year made
 

I got this Luger for shooting but have never seen one like it before. Right side has Mfg in USA by Stoeger 22 LR cal Luger Pat Pending. Left side has Luger in fancy script inside a large oval. Top shows two standing birds inside a circle. Serial number is 81801.
Anyone know when it was made? There are no dates anywhere on the pistol. Any help or comments will be greatly appreciated.
Thanks.