Rev. Rul. 75-524 can be found at

https://www.google.com/books/edition/Internal_Revenue_Cumulative_Bulletin/7HGk-iF9ZIYC?hl=en&gbpv=1&...

on page 342 (the second hit).

And from another source,

In Fred Draper, 32 T.C. 545 (1959),  the Tax Court held that, for purposes of section 117(j) of the Internal Revenue Code of 1939, corresponding to section 1231 of the 1954 Code, the holding period of an asset begins on the date of acquisition and that such acquisition occurs progressively, in the case of a building under construction, as construction (erection) of the building is completed.