I don't have the relevant texts at hand, but what you are describing rings true.
Gamma in my memory is the slope (gradient, but I am not trying to tie it to the (G bar) that some densitometry texts talk about) of the straight line portion of the HD curve that you have generated (If you know you have made what is called an HD curve is another matter.) There is another graphics arts slope related measure called CI - contrast index. I am not as sure how it is determined, but it is more involved than the straight line slope meagire of gamma.
Again, answering from work, I don't have the numbers at hand, but I think they are usually greater than unity.
Gamma is not typically listed on the product packaging, or something most workers with b&w paper worry about.
It is summarized in the technical information available from the manufactirers in most cases.
It is typically shown graphically as a series of overlapping HD curves of a variable contrast paper exposed with different contrast filters.
The slope (gamma) increases as paper filter numbers (contrast) increases.
I hope this reply helps you in resolving your query
Your post is a bit of an unusual first post.
Usually the first post runs something like... I have been lurking here for a while, and have been shooting blank camera format for blank years....
From your first post, you sound like you may be a photographer with an inquiring technical oriented and interesting approach to this craft/science called 'takin' picturs'.