Part #81-182 weight rating

Hello - I'm considering purchasing "SS Patio Door Tandem Roller, 1-1/2" Concave
Product Code: 81-182"

I purchased Primeline part like the above, however the housing is too wimpy, it isn't strong enough.
The stainless steel part attached has a stronger housing, but I need the tabs to be like the zinc part - straight off the housing not offset as in the stainless part.

81-182 - seems like the tabs are correct but is the housing rated strong? Can you share the weight rating not just for the casters but the weight rating for the housing too?