yes, that is right. I still had the old burner in my furnace
However, it seems to me that you may be able to find a burner if you can find the reference in your earlier post, or else through Suburban or a parts manufacturer. If not, you could quite possibly install your own barbecue burner if it would fit in the space. They should be just as durable as the original steel ones.
On my furnace
, the orifice for the burner was mounted in the floor of the furnace
chamber, with the burner mounted above it, as in the picture in my earlier post. The burner itself is just a hollow shaped tube with holes in it to spread the flame around. There is no reason why it should be any particular shape or size, within the limits of your furnace chamber. Just don't let it get too close to a wall so a hot spot does not develop.
I imagine that RV water heaters also have burners that might fit in your furnace.
I am sure it would be preferable to find one that is the same shape as the old one, however if you can't then I would explore the possibility of buying something else and making it fit.