actually they
did have hood props, but they rarely survive - the rubber corner thing is what's
being used here , but it doesn't give very good access if yer doin more than checkin the oil - the real prop can sort of be
seen here - it pivoted on the back of the brace bar, with a notch at the end to hook against the rod that actuates the latch, and included a cloth strap that attached to that rod to pull it up when the hood was opened
mostly by the time these trucks were 10-15 years old no one cared about buggering the paint or hood hinge and just let it flop over on the other side when opened, and the first time those rods were removed for major work, the props were left off
my
46 GMC that had about 28,000 miles on it still had them, but I never got a good pic

surely someone here with a deco model has them still and can provide dimensions, they'd be easy to make
Bill