Questions about Facebook buy

Went to buy a floor goban that was put up on marketplace and the seller ended up giving me all of this as her husband was the one who played and he passed away a bit ago. I have two questions here:

1) the smaller 9x9/13x13 reversible board is much heavier than I expected it to be. It weighs noticeably more than my 19x19 bamboo that is the same thickness. It also has a very strong smell that hits you as soon as you open the case, is there a chance it’s kaya? I’ve heard kaya has a very strong and distinct smell but I’ve never seen one before so I have no idea what the distinct smell is.

2) do these markings on the back of the floor board mean anything? The woman I bought from has no idea and google image translate isn’t giving me anything.