Roll Top Hand-Me-Down Desk

My grandfather owned this desk and from family stories, I believe he got from his parents. My father had it refurbished 30 years ago.

It measures 50x32x43, the top is held by four screws and the slats are held by canvas (no staples). There are some random numbers hand written on the bottom of the desk. The drawers seem to be all solid wood. With the exception of one drawer bottom that looks like it was repaired with plywood.

I plan to keep this desk in the family for generations to come and I'm curious how old this desk is and an approximate value.