New Mossberg 144 LSB

I'm eagerly awaiting the arrival of a Mossberg 144 LSB that I glommed at a recent auction.

Auction pics (admittedly poor)
https://www.milsurps.com/images/impo...sberg144-1.jpg
https://www.milsurps.com/images/impo...berg144a-1.jpg
Description advised:
O F. Mossberg & Sons model 144LSB bolt action target rifle. 22LR cal. 27 1/2" bbl. SN 746555. Blued finish on metal, with several areas of light oxidation, front and rear peep sights, walnut stock shows various handling marks, leather sling, 1 magazine.

One thing that is puzzling..I have never seen a muzzle like this one is depicted in the pictures. Can anyone tell me what the part on the end of the muzzle is?

Thanks

I to am interested in what reply you get to your question. I also own a Mossberg 144LSB, and mine has nothing like that on it's muzzle.