Truck model is 9314 as noted in my sig. I've come across a few references where we got a full pressure in '53, such as this thread:

https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1170525/1953-gmc-9314-canadian-model.html

In the one running video on my phone I can almost make out one of the 3 head bolts under the rocker shaft. I'll have to pull the cover to be sure.

1953 Canadian GMC 9314 w/ (factory) Chevy 235