woodchukhntr, You have gotten hold of a national treasure. I have three of the older 30-30's with slim profile barrels.
1. is similar to yours and has the same front sight, the Lyman rear sight and the "H&R 30-30 Win w/circle P" is stamped on the side of the barrel.
2.Another is stamped TOPPER MODEL 158
-30-30 Win w/circle P-
This particular barrel also has the Lyman rear sight and a dovetail mounted front sight. There is a ramp that has the dovetail in it. Can't really tell how it is attached.
3.This barrel is stamped "H&R 30-30 Win w/circle P with no rear and front sights missing. It is an on going project though it is shootable now.
Numrich has the forends for these thinner barrels and also the forend screws if needed. The screws are a different thread than todays barrels.
My kids and grand youngin's have a blast shooting these with a mildly loaded 130 grain Hornady SSSP bullet.
A pic of the three amigos;
Dovetail Front Sight;