hi Jacques
I did have a few of those log book holders at one time, I think somebody had a big heap of them and a few of us grabbed some , probably back in the 1970's or 80's.
Anyway I always thought the cover was canvas
I am not at issue with Jason's suggestion as he might have a complete original holder .
Do you have a log book ? They were around , Hudsons stores in Bourke st , used to sell them as note books for 50 cents
I did buy some of the carrier log books from them .