My dad"s 1950 H came with the strap, then about 1960-1962 as I climbed on the tractor I saw he had put on the barrel shaped roller.
I don"t really know why he did that but I thought it looked good. I never thought to ask him about it and now it"s far too late.
I take the tractor to shows and rides and no one ever asks about that as I think anyone younger than me just assumes it came from the factory like that.
I still think it looks good.
LA in WI