Help dating the switch of the Crosman 160 to the slimmer stock

[45flint]

I’m about finished loading my Crosman Salesman’s case and am trying to date it by the guns it was made for.  I have the earliest date it could have been made given it includes a first model Crosman 400 as 1957.  I think the inclusion of a first model stock on the 160 will limit the high end?  The Blue Book says the 2nd model 160 ended in 1959.  The die cast trigger started in 1960, which I assume would have changed the stock to the slimmer new version? The 160 seems to have been the first rifle fitted with the new die cast trigger.  Does anyone have any information or 160’s with date codes that would confirm the year of the change of stock to be 1960? 

[unionrdr]

My 160 is a variant one by virtue of it's having no barrel band. And the stamped steel trigger guard and pinned rocker trigger. It uses a small spacer between the barrel & gas tube as a support instead of a band on the barrel. No raised comb or cheekpiece either. That's what makes it a variant one...the first of it's kind from the initial 1955-1956 model run. The variant two would come in 1957 with the cheekpiece, barrel band and one-piece trigger housing that was very good. Oddly enough, Crosman no longer lists the 160 variant one or two (55-62). But now only the 160 variant 3 from 1962-1971.

[45flint]

You made me think of searching Crosman, they still lists all three variants here:

https://www.crosman.com/discover/crosman/crosman-product-dates

They says the same thing as the Blue Book second variant ends in 1959, the third variant with the die cast trigger starts in 1960?
Again I assume the die cast trigger must start the new stock with cheek swell?  Thus seems to me the case must be made from 1957 to 1959?  Pretty narrow time frame.

[unionrdr]

Odd that the other list they have doesn't show all variants? Saved this link.