Of course I can't tell if it's the original stock but it does appear to be period correct. The plastic or resin or whatever trigger is typical of the later T01 triggers and the blade of the T05 looked the same - less one adjustment screw, of course. Note the rear sight. Older sights would rotate to one of four different notches. At some point Diana introduced the "improved" sight which "lost" that rotating piece. Perhaps that came with the T05 trigger guns. Perhaps not. Changes to the Diana air rifles from year to year are very slight but they do happen.