Welcome. If you do decide to shoot it, have a competent gunsmith check it first. The gun was known as the "widow maker" because if certain internal became worn, it could fire with the bolt unlocked, thus putting the bolt into the cranium. The following stolen from another site.
Now as far as the safety checks for the Marlins,
there are four that can be done without taking
the gun apart. These will tell you immediately
if the bolt has any chance of coming out the
back of the receiver. (Notice I didn't mention
the possibility of a cracked receiver or you
are planning on shooting magnum turkey loads.
1- hammer follows bolt
With an empty gun, hold the trigger back and
gently slide the bolt forward with the pump
arm. If the hammer follows along behind, STOP.
It means the secondary sear spring is broken
and the gun could, BIG MAYBE, slam fire without
the breech locked.
2- try to puch firing pin forward out of bolt face.
I'll assume the hammer stayed cocked. Open
the receiver and apply pressure to the back
of the firing pin with your thumb, it should
not move much and come up solid before the
firing pin tip protrudes from the breech face.
If it protrudes from the breech face, STOP.
This means the firing pin locking horn on
the rotating breech lock is not functioning.
(read, worn off, broken, tampered with, etc.)
3- pin can go forward when in battery
close the action slowly and deliberately with
pressure applied to the rear of the firing
pin with you thumb.As the rotating breech lock
falls into battery the firing pin will become
free to push through the face of the breech.
THIS IS NORMAL.
4- action cannot open when cocked and before fired.
Last, but by no means least, Gently lower the
hammer to rest on the firing pin or use your
thumb to depress it, (if its loaded, always
use your thumb). The action should NOT open
with rearward pressure applied to the forearm.
If it opens, STOP. The recoil lock isn?t engaging
properly. To get the breech open you have
to depress the safety latch and the firing
pin simultaneously, up near the hammer on the
older models or down near the trigger for newer
models,to open the bolt. THIS IS NORMAL. This
test tells you if the locking lug is rotating
completely into battery, and not just sort
of in battery. It also may tell you if the
lock is broken, or in need of adjustment.
(It takes a trained ear to hear it lock in.)
If ANY of those tests failed the gun will need
to be repaired.