Help me identify these 3 ports on my 83 (see pics)

[Tall Pine]

Hello all. My first post on here at go2gbo, a great site. Well, I just took the plunge and bought my first FA in 454. Its really nice, and I got it locally at what I think is a good deal. Premier grade 6", trigger stop, micarta grips, inverted crown (very cool look), millets sights, jeweled h&t, lanyard, and a 3 hole porting.?.?
 
Does any one on here have similar 3 hole porting? I have only ever seen 2 or 4 hole porting. It looks factory to me, and the side ports look like traditional magnas. But Im very curious about the top port. Never seen one there, and am wondering how that is going to look when I fire some hot 454 through her. Im thinking Volcano.?.?.? I am assuming it wont interfere with my aim because once I see the flame that bullet is long gone. Maybe on attempted fast follow up shots though.
 
Any help you can offer as to the history or commonality of the top port I'd appreciate it, its really got me curious. Even if you say its gonna csuck, I don't care, I love her already.     Thanks, and enjoy the pics.
 

 

 

 

 

 

[Les Staley]

Be sure to wear ear protection...or by the time you see the flame your HEARING will be long gone..nice gun..just got my first FA...a 97 in 45 Colt.   Congrats..

[Ken ONeill]

Magnaport has done the 6" FA guns with either 2 ports or 3 ports (buyer's choice) for at least a dozen years or more. The 3 port is claimed to give an extra recoil reduction. Unless you're shooting at night, you won't see any more muzzle flash than the 2 port. I never see muzzle flash attributable to the magnaport jobs. You'll see muzzle flash at dusk through an unported gun anyway.

[Tall Pine]

Thanks Ken, I appreciate the info. I can see where the 3rd hole right over center would give the effect you describe. When I get around to shooting it in a few weeks I'll post my experiences.
 
Thanks again,
Tall