If you are going to use it regularly replace both but keep the originals.
A true problem with ”keeping” the original 300 crystals are that very seldom are you able to re-install them without any damage / cracking as they are very fragile. So just think twice of being able to “put it back again” as it would never had left the watch. Just my 2 cents.
Acrylic crystals can degrade over time and lose structural integrity, especially if they have had a good dose of UV (sunlight).
One good bump could cause the crystal to shatter and you end up with bits of plastic all over the dial and hands.
For a watch of this value, I'd fit a new crystal to safeguard the innards and keep the old one in case some collector sees value in it.
Just my view.
That is a very cool watch. Wear it with joy.