Model 57 question

[Bloodhound]

I came across a Model 57 6 inch with a recessed cylinder but the barrel is not pinned...the gun all looks original...but not having the barrel pinned has me wondering...whats up?

 

[Pizza Bob]

Transitional gun.

 

[Bloodhound]

I thought that might be the case...it has had a rough life...but is still tight and the bore and cylinder look good