It's a 2 leaf sight, Mike. To my eye, looks just like the #12 leaf sight in the 1900 catalog - price $1.

And, yes, it would have had a white triangle at one time.

Page 40 on this:
http://stevespages.com/pdf/savage1899.pdf

“The Savage 99 Pocket Reference”.
All models and variations of 1895’s, 1899’s and 99’s covered.
Also dates, checkering, engraving.. Find at www.savagelevers.com