inland m1

The ramp front sight looks similar to one typically found on Winch Model 70's. Usually see them with some kind of hood.

The barrel says general motors behind front site.on the flat side there is a 3 toward the front and strange enough it has symbols of a man,a chair an rectangle with line drawn diagonal on the rear side.????

there is no dates anywhere.the ser num 405351 should indicate early model.i will send a pic soon.

pics of the barrel flat would be helpful

Looks to be a early barrel. If you take off slide there may be a flaming bomb nearpiston.

Got to check when they had undated barrels show up sporadically

any idea how to get an original front site to replace thus one?

That one was probably silver soldered on or tapped and threaded,  but before you remove it, you should mike the barrel to make sure it hasn't been turned down.

According my "Harbor Freight" Digital Calipers  it should measure approximately .5825 -.5835 at the area of the sight.

found an old caliper,seem barrel measures about .4785,around the front site.

I can't see any way to return that to original condition short of a barrel-change, or some real imaginative metallurgy on the part of a good machinist. Like turning the muzzle down enough to install a sleeve to the original barrel dimensions. Then you have the channel for the key to fit...etc. One could install a sleeve and one of the aftermarket commercial set-screw style sights. Seems like any reasonable fix is going to come close to a barrel replacement in $$$. On the other hand, it's not broken either I guess. May have to just shoot it like it is. This is only a problem in view of collecting and not shooting.