Thanks!
The Hand made in USA stamp is on the blade in addition to USA under the CASE XX, if that makes a difference.
Unless someone with far greater knowledge than mine comes forth such as Perry Miller - I'd say that makes no difference.
None of the blade stamped references that I have indicate the 'Hand made' thru 1970 stamped blades as being part of the official 'date' indication. If you think about it a bit - all of the Case knives were hand made.
The Bulldog was one of the more unusual offerings.