Two definite trains of thought on these rifles are...

1, all the guns that were going to blow up did and it's a non issue...

2, low numbers aren't safe and are waiting patiently to fracture.

Thing is, if it breaks...it doesn't slowly crack or give you a warning. It shatters like glass. Pics are available...I personally wouldn't shoot one that early, and nothing in clear conscience below about 8XX XXX...opinions may vary...

By the way, welcome to the neighborhood...