Originally Posted by Allen-frame

Linda ,and Doc.

I have records of S175xxx , S17624x , and S1822xx, being 4 screw non model marked Highway Patrolman.
Lindas' 4 screw falls within these runs. Maybe the 4 screw 44 Magnum was made in small batches ,,to order ,back then.

I personally feel that 4 screw non model marked N frames were produced in smaller numbers than Docs estimate. Maybe closer to 12000 to 14000.
This is only from keeping records of Ser #s that fall into this range. Not from any long term experience such as Docs.

S1829xx is a model marked 28. this eliminates some on the end of the equation.

Hope this helps.

Regards ,,Allen