Old FH race cranks ( before the 8BA )

[3W Hank]

I did checked out this crank today.
Std on both rod & mains.
Long nose and big mains/rods so it must be a 1939 early as rear seal was a slung.
Are that design bad, or caused leaks ?
If I got it right under 39 it was both slung and rope, so it cant be a 1940's crank.
Weight was 70.5 LBS or 32 kg.
Don't know weight of a 1945 crank or a Merc 4".