http://www.picturetrail.com/sfx/album/view/24563589

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=195233&page=all

Cornell Pubs has lots of Pieper resources
https://www.cornellpubs.com/searchResults.php

If you would post a full size up close image of every mark on the barrel flats and just forward of the flats we might be able to provide a date of manufacture, or look here
http://www.shotgunworld.com/bbs/viewtopic.php?f=5&t=232252