Since the film's focal point was the parade passing a singular point on the freeway (rather than the facility itself), not at all surprising for a family-sourced film, there's no indication of signage at the '59 opening. My question is: was it immediately signed as I-35E upon opening or simply US 77, the multiplexed route?
P.S. -- looking at the other links, it looks like a mix; one shot shows a I-35E shield (with a very small "E" tucked under the number!), while another shows only a US 77 shield. Sort of reminds me of L.A. during that same time frame -- some freeways (I-10 in particular) got a pretty complete signage treatment early on, while others didn't see shields until well into the '60's.
