As you mentioned there isn’t a definitive or specific cutoff date / serial range for when the stock cutout slot was omitted (but just a general idea of a range when it was widely phased out), as some early spare frames were reused for later pistols. I am just thinking off the top of my head, but I do recall York’s book had an example of a K-serial pistol that had a stock slot cutout.if its a true no letter block pistol it will have the cut. I think they did into the early b block ? But, im not 100% sure. Like all this stuff there is a gradual progression of change..
Bill yorks book is back in print I think ? its a must for radom folks. Also axis pistols has most all the info on there as well..
the p35p and p35b have the same basic evolution.
Back in the mid-'70s a friend owned K9110. No acceptance stamps on either frame or slide...Two really nice Radoms, bookends to occupied production. That K block is LATE. Not sure what the last serial number known is but I think it’s around 9100. You’re only a few hundred off. I’ll check the books tomorrow.
Bill yorks book is back in print I think ? its a must for radom folks
Get the color version instead of the black and white.