The PDP-8/E, which came out in the same year, had a boot ROM if you were using DECtape as the system device for OS/8.  The bootstrap for the TD8E DECtape controller was a full device driver 128 words long, way beyond human toggle-in capability.  It was put up in addresses 77600-77777, which meant that you could only have 28 kwords rather than the full 32 kwords of RAM.

In principle I suppose you could have toggled in the RIM loader (17 words) and read in the TD8E bootstrap using either Model 33 or high-speed paper tape, but I doubt if anyone did that.  RIM format alternated between addresses and values, with each taking up two characters on the paper tape.