What's the earliest original laminate stocked SKS45 that you've seen?
They were most certainly around in '57 with the И series:
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1957_Tula/BM5559__stock.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1957_Tula/BM5559__right_rear.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1957_Tula/BM5559__crossbolt.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1957_Tula/BM5559__crossbolt2.jpg)
I have two candidates for a '56 Д series, though I don't have great photos of either. I think cases could easily be made against both of these, but here they are anyway.
#1) HP prefix, '55 dated receiver cover, gorgeous ruby red laminate stock. I think maybe one could make a case that there may have been an old number on the stock:
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/HP3382__receiver.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/HP3382__receiver_cover.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/HP3382__receiver_cover2.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/HP3382__stock.jpg)
#2) KA prefix, blank receiver cover, somewhat dark laminate stock. I wish I could see the other crossbolt and the right side of the stock. The stamps on the wrist sure look crisp though, but then you wonder why so many, and why on top of each other?:
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/KA7186__stock.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/KA7186__left_lug.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/KA7186__receiver.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/KA7186__left_whole.jpg)
(http://i1352.photobucket.com/albums/q647/jelucer/Russian/1956_Tula/KA7186__receiver_cover_rear.jpg)