The "T" on the sight means "Törped" wich is a pionted, boattail bullet of 140 grains (also called M/41 Prick wich is actually 9.07 g (139 grains) @ m.v. of 793 m/s (2600 fps)) as opposed to the original load, namely M/94, round nose, 156 grains, (10.10 g) @ a m.v. of 2300 fps (700 m/s)).
The "T" sights are actually calibrated for a 300 m zero, so you're right on. If you want to change it, there are different front sight heights readily availlable from many companies WW GP shall ahve them, so does Numrich.