So you hope to etch your new windshield with the 1970-proper wording? WOW! I'm not sure who would know but that's such an amazing bit of Morgan trivia that I have got to help you.
For starters I'm going to look at the glass on my wife's 1959 DHC. (The windscreen on my 1961 is not original -- the previous owner broke the glass while trying to put the top up.) It will be a few days, because there's 29 inches of snow in my yard.