How to tell a “Long Action w/ a 3 Screw Trigger”

[bootsmcguire]

+1, only action I've seen the 3 screw trigger on.

As from the factory, yes, only one I've seen also.

However it is quite possible to put a 3-screw on the newer actions, so don't rule it out if the rifle appears to be modified in any way as you search the used racks. I have done it and it works quite well.