Never have. Did we have IRAs 40 years ago?

Since 1974.  You remember that year, right?  Nixon resigned.  Twelve years later, Reagan repealed rollover of gain from sale of primary residence.  

From IRS: "If a surviving spouse receives a distribution from his or her deceased spouse's IRA, it can be rolled over into an IRA of the surviving spouse within the 60-day time limit, as long as the distribution is not a required distribution, even if the surviving spouse is not the sole beneficiary of his or her deceased spouse's IRA". It makes no mention of it being a 2nd, 3rd, of 4th spouse, only spouse. I suppose there might be time limits in the actual code. 

TRA 86 did a lot more than that.

Yes I remember 1974 but not the bit about IRAs.

In 1974 I was more concerned about studying for my high school calculus test than I was worrying about IRA rules.🤔 

See, that was your mistake.  If you had dropped out of high school and taken that job with WalMart, joining their employee stock purchase plan, you wouldn't be where you are today.  (In other words, still working.)

The first Walmart didn't hit Minnesota until 12 years later, so if I dropped out of high school, I would have had to go to work for McDonalds.  Wait, we didn't have a McDonalds in our area at the time.  Ah, what the heck.  Good thing I kept studying for that calculus test.

FYI Traditional IRAs were introduced with the Employee Retirement Income Security Act of 1974 (ERISA) and made popular with the Economic Recovery Tax Act of 1981.