I think that going back to their website or contacting the company by phone might be helpful. I spent some time looking for these numbers and i only found one reference and that was one that was for sale for 175 after it was bead-blasted and repainted. It was then that i noticed that it looks a lot like the one laying on my garage floor that I got with my camper when i bought it last year. It's so rusty, I couldn't tell you if the part numbers are the same or not. But you're right, it does look bigger and more heavy duty then the one's ive seen out there.
Sorry i couldnt be more help.
Where we've been:
2000 Rockwood Roo M-18 Hybrid
2006 Dodge Ram 2500 Auto 5.9 Diesel
Gone but not forgotten -1986 Rockwood 1003 PUP