Those guns are called; "Flatgates" by the Ruger folks. Generally collectable to most. The serial numbers from 1-150000 were made with a slightly smaller bore diameter than the later convertibles, (post 150000) where .22 Magnum ammo was able to be used. As such,, many enjoy shooting these guns because they are quite accurate.
That flat loading gate was the original design. An aftermarket company (Premier) started offering a rounded gate as an accessory. Ruger changed to the rounded loading gate & Premier's business in the gates died.
While some may think they are ugly,, value wise,, I've never seen them be a detractor when having the flat loading gate.