Re: 300 case
On mine, I didn't check again, I'll try to remember to when I get home, the date was in the format xx/xx/83. I'm pretty sure it was on the tailhousing. that would have been a casting date, not an assy date, but it's better than nothing.
The Scout case has the short output shaft (being an '80) and has the same bolt pattern as the earlier Jeep D20's and Spicer 18's. It's basically a bolt on replacement. A tad longer, I think.