It is important that you measure the front sight dovetail insert for compatibility with your Marlin 19895GBL. The sight set that is closest in height (front sight) should be correct for this rifle. Measure front sight dovetail insert from the top of the sight to the bottom of the dovetail. The front sight heights are as follows:
TG109 .343”
TG112 .450”
TG114 .500”
Please make sure your front sight does have a 3/8” dovetailed front sight blade insert in its base ramp. We always recommend to have an experienced gunsmith perform replacement sight installations of any kind.