Many of the cases Taylor provided in the early days were well made but, as you note, they didn't always fit the guitar well. I bought my 615 used so I don't know if the case I got was supplied by Taylor, but it was not a good fit. The guitar wasn't loose inside, but its body only came in contact with four small areas inside the case, and I was never quite comfortable with that. Fortunately, in '02 I got a great deal on mid-90s Taylor-branded jumbo case, so I don't have that ill-fit problem anymore. The case was used, but it looked new.
That 615 was a great find, though. I bought it in '88 when Taylor was still an up-and-comer and even new ones were less expensive than Martin, Gibson and Guild equivalents. I played seven or eight guitars that day, and the only one I liked as much was a new J-28 which, even with a discount, would have cost at least 50% more than I paid for the 615. I went into hock for it, but I've never regretted it.
BTW, nice catch on that 650. Taylor never made many 12-string dreads, so that guitar is fairly uncommon.