Original Spring Loaded FP on early Russians

[Gator Monroe]

Did the 1949 & 1950 Russians remain the only Russian SKS with original factory Spring loaded Firing pin or were some early 1951 rifles also included before that feature ceased ??

[running-man]

As far as I know, the spring loaded firing pin and it's associated specialized bolt & bolt carrier went away after the transitional '50 was finished and the true '50s were being churned out.  I've never heard of a spring loaded FP in a '51 from the factory. 

There are lots of Murray kits out there though...