Certainly looks like a model 1904. Can you read any dates or anything on the barrel?

Never seen one marked "Sport" before.

The trigger guard has been changed I believe it should have a curl to it, the rear sight has me confusted to, looks like the place a factory peep would have been but you have a buckhorn in it. I think it's a 1904 thats been modified somewhat. The bolt handle looks like it's off a model 3.

Can you see a serial number on the side of the chamber where you load the gun?