45 to 22 conversion unit by Stoeger help

I have just purchased this unit and am looking for any info the folks in this form can give me. Year of manufacture,how many produced,any info at all. The unit markings are A F Stoger Inc. N Y on the left side,it has a blue finish,6 1/8" tip up barrel with a spring loaded ejector,and a dovetail rear sight. It came in a leather holster that has a flap with a snap and a belt loop. Thanks in advance Dick