Info on model 12 skeet w/ Cutts

I have my grandfather's model 12 skeet, serial #721xxx, 12 ga.
I believe its circa 1936, From the postings I've read here. Was just curious as to the value, and if the Cutt's Compensator may have been installed at the factory? I read somewhere that aftermarket installations tended to loosen up on heavily used guns.(this one is rock solid) There is a choke mark on the left side of the barrel, "WS1", but I heard somewhere that some skeet guns were stamped ws1, and the compensator was installed at the factory. Is there another way to tell?
The rib is a solid, matted rib. The numbers on barrel and receiver match. The wood is pretty good,no cracks and 2 or 3 small nicks and appears to never have been varnished, but oil finished. The bluing is probably 80%, the magazine tube being the worst. The bore is spotless.
Actually, the value is basically a secondary question, my main concern is whether or not I can use it on a regular basis. I've just begun to shoot skeet regularly, and frankly cannot find another gun which "fits" me as well as this one. I tend to shoot 2 or 3 rounds of skeet per week, and this being a 67 year old gun, am a little concerned as to it's longevity. I know they were extremely well made, but my grandfather shot it quite extensively in skeet competitions up through the 60's, and my brother shot it regularly up through the 90's. I have had the gun for several years now, and have shot it pretty regularly myself. My point being, this gun could conceivably have shot well over 100000 shells! There must be limits. While it still functions flawlessly, it would kill me to break it. Is this a legitimate worry? I've been told by old timers at the range that it'll outlive me, but I still worry.