Lots of possible variation here due to location and elevation.

Where is this building?

In the 1973 edition of the UBC, the furthest back I have at my fingertips, Table 23B for Minimum Roof Live Loads gives a breakdown of 10 to 12 psf on the major structural components depending on the tributary area seen.  It also has a note at the bottom that "where snow load occurs, the roof structure shall be designed for such loads as determined by the Building Official."  As I saw no other reference to any slo load tables in this edition, the call may have been delegated to the local BO at the time of this UBC and those prior.

Mike McCann
McCann Engineering

The exact location is Bend, Oregon.  I can track snow loads myself back to 1971 because I have the “Oregon Snow Load Manual - Snow Load Analysis for Oregon” published in 1971.  However, this still doesn’t get me back to 1962.

Msquared48, does your 1973 edition of the UBC give minimum Floor live loads for office buildings?  Mainly I need to know whether load requirements have increased or decreased since 1962.  My assumption – they have increased, but it is worth it to check.

Table 23-A shows 50 psf for offices.  No mention of partition loads...

Regarding the snow loads - that info should be available through the Bend, Oregon Building Department, or the county in which Bend lies, as implied in the note of Table 23-B I mentioned before.  I assume you have checked with them though to no avail?

Mike McCann
McCann Engineering