(all pb)
>COBOL used Unix date format for the most part
No, this is absolutely false. Unix didn't even exist. SS's computers started in the mid 50's, probably using FLOW-MATIC.
First, you couldn't even type in a date directly until 1974 - sauce - https://rosettacode.org/wiki/Category:COBOL
Second, the date format wasn't anything like what they are saying,
December 25, 1986 would be expressed as 861225, only using 2 years for the date.
Sauce - (page 72) https://www.govinfo.gov/content/pkg/GOVPUB-C13-d0cd47d3539e1d225361316057506135/pdf/GOVPUB-C13-d0cd47d3539e1d225361316057506135.pdf