I am going to put my hat in this ring.

I'm blessed to have a mint M&P from around 1930. The blue was all done in one shot and it all matches perfectly.

We also have several from the 50's and 60's that are as mint as the M&P. One little difference. These pieces were done in batches. Get it in bright day light and each of the major components has just a bit different shade of blue. The blue on the M&P on the other hand is all the same, front to back, top to bottom.

As far as the stock fitting is concerned, there is simply no comparison. The M&P fit, finish and match is miles ahead.

The 1930's production was built in age of craftsmanship !!!

Look at a mint 80 year old example and you'll see what I mean. The quality is simply stunning.

That's my vote