Personally I would not weld a coupler on if it is boltable. Nothing wrong with bolts and it makes it easily replaceable if needed.
Which Bulldog you looking at that requires or even suggests welding on the cast part? Don't think such exists.
Skyco.
You are correct and I read the information wrong. The A frame on the Bulldog is not cast but the part that clamps the ball is. The one I need for the A frame tongue of the trailer is a weldable unit.
I'm going the have the people that sell the coupler weld it on for me. I am not a certified welder and I don't want to take any chances with safety.
Clem