First plum bolt carriers and bolt appeared on SVTs in 1941, in 1942 most of the rifles if not all had plum bolt carrier and bolt. Moreover Tokarev was evidently experimenting with bluing of these tho parts as even some of his early trial rifles had plum bolt carriers. It is all well known facts. Most of the Finn capture SVT-40s and 38s are of 1939, 1940 and 1941 and thus have while bolt carriers and bolt. Most but not all. So one's plum bolt might be refubed blued, but also might originally blued.