NGD! 10/22 content :-)

It's their carbine model with a grey laminate stock. And some previous owner stuck on a flash hider or muzzle brake thingy. That part isn't stock.

Nice looking Ruger. What are you going to do with it? Any mods or simply use it as it is?

The 3 digit prefix of the serial number will tell you when it was made as well.

Looks like a fairly new-ish one, based on the magazine release

It also appears to have sling studs added, the one on the front barrel band isn't standard

And someone moved the front sight to that silly flash hider thingamijig

Is the bolt hold-open modified as well? If you lock the bolt to the rear, do you have to "rock" the BHO plate or can you just pull the bolt to the rear and let it go forward?

And someone moved the front sight to that silly flash hider thingamijig

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It's not moved, the flash hider slips over/around the front sight base.

It's not moved, the flash hider slips over/around the front sight base.

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Makes sense, if I squint at the photo correctly
That flash-hider should come right off with a setscrew or similar, then, right?

Yep.

The 10/22 uses a set-screw, the same muzzle device for the mINI-14 uses a roll pin.

http://www.ruger.com/products/1022DE/specSheets/1109.html

So many experts...

The swivel studs appear to be factory. The only add-on I see is the muzzle break

Nothing wrong with the muzzle brake. Lots of people use them on a 10/22. It prevents you from accidentally filling the muzzle up with dirt. I use a 20ga mop to clean the muzzle brake on my 10/22.

I will probably take the muzzle break (sic) off tonight

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Is it a brake or a flash hider? It looks like a flash hider, but I cannot see the picture that well.

It's a flash suppressor. It does protect the muzzle.

My stainless/laminate carbine model came with swivel studs 20yrs ago.

It's obviously a later model, judging by the extended mag release and matte finish.